概述
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<h1 id="-" style="margin: 20px 0px 10px; padding: 0px; font-weight: bold; color: black; font-size: 24px; border-bottom: 2px solid #aaaaaa;">二叉搜索树
<p style="margin: 0px 0px 1.2em !important; font-size: 16px; line-height: 1.75em; padding-right: 0.5em; padding-left: 0.5em;">二叉搜索树是一种特殊的二叉树,它的特点是:
一个图例:
搜索树的这种关系,我们可以用它来实现有序映射
搜索树的特性,采用中序遍历的方式可以使得遍历结果是按照从小到大的顺序排列的。了解中序遍历可以参考
:
<span class="hljs-keyword" style="font-weight: bold;">if</span> right(p) <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span>:
walk = right(p)
<span class="hljs-keyword" style="font-weight: bold;">while</span> left(right(p)) <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span>: <span class="hljs-comment" style="color: #738191;"># 找最左</span>
walk = left(walk)
<span class="hljs-keyword" style="font-weight: bold;">return</span> walk
<span class="hljs-keyword" style="font-weight: bold;">else</span>:
walk = p
ancestor = parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while</span> ancestor <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span> <span class="hljs-keyword" style="font-weight: bold;">and</span> walk == right(ancestor): <span class="hljs-comment" style="color: #738191;"># 当walk是左孩子时或walk是根节点时停止</span>
walk = ancestor
ancestor = parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return</span> ancestor
<span class="hljs-keyword" style="font-weight: bold;">if</span> right(p) <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span>:
walk = right(p)
<span class="hljs-keyword" style="font-weight: bold;">while</span> left(right(p)) <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span>: <span class="hljs-comment" style="color: #738191;"># 找最左</span>
walk = left(walk)
<span class="hljs-keyword" style="font-weight: bold;">return</span> walk
<span class="hljs-keyword" style="font-weight: bold;">else</span>:
walk = p
ancestor = parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while</span> ancestor <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span> <span class="hljs-keyword" style="font-weight: bold;">and</span> walk == right(ancestor): <span class="hljs-comment" style="color: #738191;"># 当walk是左孩子时或walk是根节点时停止</span>
walk = ancestor
ancestor = parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return</span> ancestor
<span class="hljs-keyword" style="font-weight: bold;">if</span> right(p) <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span>:
walk = right(p)
<span class="hljs-keyword" style="font-weight: bold;">while</span> left(right(p)) <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span>: <span class="hljs-comment" style="color: #738191;"># 找最左</span>
walk = left(walk)
<span class="hljs-keyword" style="font-weight: bold;">return</span> walk
<span class="hljs-keyword" style="font-weight: bold;">else</span>:
walk = p
ancestor = parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while</span> ancestor <span class="hljs-keyword" style="font-weight: bold;">is</span> <span class="hljs-keyword" style="font-weight: bold;">not</span> <span class="hljs-keyword" style="font-weight: bold;">None</span> <span class="hljs-keyword" style="font-weight: bold;">and</span> walk == right(ancestor): <span class="hljs-comment" style="color: #738191;"># 当walk是左孩子时或walk是根节点时停止</span>
walk = ancestor
ancestor = parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return</span> ancestor
:
k == p.key():
p
k < p.key() T.left(p) :
search(T,T.left(p))
k > p.key() T.right(p) :
search(T,T.right(p))
p
:
<span class="hljs-class"><span class="hljs-keyword" style="font-weight: bold;">class</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_item</span><span class="hljs-params">()</span>:</span>
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__init__</span><span class="hljs-params">(self,key,value)</span>:</span>
self.key = key
self.value = value
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__eq__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key == other.key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__ne__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key != other.key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__lt__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key < other.key
<span class="hljs-class"><span class="hljs-keyword" style="font-weight: bold;">class</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">Position</span><span class="hljs-params">(BinaryTree.Position)</span>:</span>
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">key</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.element().key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">value</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.element().value
<span class="hljs-class"><span class="hljs-keyword" style="font-weight: bold;">class</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_item</span><span class="hljs-params">()</span>:</span>
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__init__</span><span class="hljs-params">(self,key,value)</span>:</span>
self.key = key
self.value = value
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__eq__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key == other.key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__ne__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key != other.key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__lt__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key < other.key
<span class="hljs-class"><span class="hljs-keyword" style="font-weight: bold;">class</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">Position</span><span class="hljs-params">(BinaryTree.Position)</span>:</span>
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">key</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.element().key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">value</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.element().value
<span class="hljs-class"><span class="hljs-keyword" style="font-weight: bold;">class</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_item</span><span class="hljs-params">()</span>:</span>
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__init__</span><span class="hljs-params">(self,key,value)</span>:</span>
self.key = key
self.value = value
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__eq__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key == other.key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__ne__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key != other.key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">__lt__</span><span class="hljs-params">(self,other)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.key < other.key
<span class="hljs-class"><span class="hljs-keyword" style="font-weight: bold;">class</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">Position</span><span class="hljs-params">(BinaryTree.Position)</span>:</span>
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">key</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.element().key
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def</span> <span class="hljs-title" style="font-weight: bold; color: #0048ab;">value</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword" style="font-weight: bold;">return</span> self.element().value
404_17@ 404_17@404_17@:@H_404_17@ 搜索算法"""@H_404_17@ 404_17@ k == p.key(): 404_17@ p 404_17@ k < p.key(): 404_17@ self.left(p) 404_17@ 404_17@ 404_17@: 404_17@ self._subtree_search(self.left(p),k) 404_17@: 404_17@ self.right(p) 404_17@ 404_17@ 404_17@: 404_17@ self._subtree_search(self.right(p),k) 404_17@ p
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_subtree_firstposition@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""返回树的最左节点"""@H40417@
walk = p
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ self.left(walk) <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
walk = self.left(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ walk
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_subtree_lastposition@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""返回树的最右节点"""@H40417@
walk = p
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ self.right(walk) <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
walk = self.right(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ walk
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_subtree_firstposition@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""返回树的最左节点"""@H40417@
walk = p
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ self.left(walk) <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
walk = self.left(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ walk
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_subtree_lastposition@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""返回树的最右节点"""@H40417@
walk = p
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ self.right(walk) <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
walk = self.right(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ walk
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_subtree_firstposition@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""返回树的最左节点"""@H40417@
walk = p
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ self.left(walk) <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
walk = self.left(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ walk
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">_subtree_lastposition@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""返回树的最右节点"""@H40417@
walk = p
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ self.right(walk) <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
walk = self.right(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ walk
404_17@ 404_17@404_17@:@H_404_17@ 404_17@ self._subtree_first_position( self.root()) 404_17@ len(self) > 404_17@ 404_17@ 404_17@
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">last@H40417@<span class="hljs-params">(self)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_lastposition(
self.root()) <span class="hljs-keyword" style="font-weight: bold;">if@H40417@ len(self) > <span class="hljs-number">0@H40417@ <span class="hljs-keyword" style="font-weight: bold;">else@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H404_17@<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">before@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""前驱位置"""@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.left(p):
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_lastposition(self.left(p))
<span class="hljs-keyword" style="font-weight: bold;">else@H40417@:
walk = p
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ above <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ walk == self.left(above):
walk = above
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ above<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">after@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""后继位置"""@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.right(p):
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_firstposition(self.right(p))
<span class="hljs-keyword" style="font-weight: bold;">else@H40417@:
walk = p
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ above <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ walk == self.right(above):
walk = above
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ above
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findposition@H40417@<span class="hljs-params">(self,k)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.isempty():
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ p
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">last@H40417@<span class="hljs-params">(self)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_lastposition(
self.root()) <span class="hljs-keyword" style="font-weight: bold;">if@H40417@ len(self) > <span class="hljs-number">0@H40417@ <span class="hljs-keyword" style="font-weight: bold;">else@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H404_17@
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">before@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""前驱位置"""@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.left(p):
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_lastposition(self.left(p))
<span class="hljs-keyword" style="font-weight: bold;">else@H40417@:
walk = p
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ above <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ walk == self.left(above):
walk = above
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ above
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">after@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""后继位置"""@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.right(p):
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_firstposition(self.right(p))
<span class="hljs-keyword" style="font-weight: bold;">else@H40417@:
walk = p
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ above <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ walk == self.right(above):
walk = above
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ above
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findposition@H40417@<span class="hljs-params">(self,k)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.isempty():
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ p
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">last@H40417@<span class="hljs-params">(self)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_lastposition(
self.root()) <span class="hljs-keyword" style="font-weight: bold;">if@H40417@ len(self) > <span class="hljs-number">0@H40417@ <span class="hljs-keyword" style="font-weight: bold;">else@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H404_17@
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">before@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""前驱位置"""@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.left(p):
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_lastposition(self.left(p))
<span class="hljs-keyword" style="font-weight: bold;">else@H40417@:
walk = p
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ above <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ walk == self.left(above):
walk = above
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ above
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">after@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-string" style="color: #0048ab;">"""后继位置"""@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.right(p):
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ self._subtree_firstposition(self.right(p))
<span class="hljs-keyword" style="font-weight: bold;">else@H40417@:
walk = p
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ above <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ walk == self.right(above):
walk = above
above = self.parent(walk)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ above
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findposition@H40417@<span class="hljs-params">(self,k)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.isempty():
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">return@H404_17@ p
404_17@ 404_17@404_17@:@H_404_17@ 404_17@ self.is_empty(): 404_17@ KeyError(404_17@+repr(k)) 404_17@: p = self._subtree_search(self.root(),k) 404_17@ k!=p.key(): 404_17@ KeyError(404_17@ + repr(k)) 404_17@ p.value()
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">setitem@H40417@<span class="hljs-params">(self,k,v)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.is_empty():
leaf = self.add_root(self.Item(k,v))
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p.key() == k:
p.element().value = v
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
item = self.Item(k,v)
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ p.key() < k:
leaf = self.addright(p,item)
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
leaf = self.add_left(p,item)<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">iter@H40417@<span class="hljs-params">(self)@H40417@:@H40417@
p = self.first()
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ p <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
<span class="hljs-keyword" style="font-weight: bold;">yield@H404_17@ p.key()
p = self.after(p)<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">mapdelete@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.left(p) <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ self.right(p): <span class="hljs-comment" style="color: #738191;">#两个孩子都有的时候@H404_17@
replacement = self._subtree_lastposition(self.left(p)) <span class="hljs-comment" style="color: #738191;">#用左子树最右位置代替@H404_17@
self.replace(p,replacement.element())
p = replacement
self.delete(p)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">delitem@H40417@<span class="hljs-params">(self,k)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H404_17@ self.is_empty():
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ k == p.key():
self.mapdelete(p)
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@
<span class="hljs-keyword" style="font-weight: bold;">raise@H40417@ KeyError(<span class="hljs-string" style="color: #0048ab;">'Key Error'@H404_17@ + repr(k))
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">setitem@H40417@<span class="hljs-params">(self,k,v)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.is_empty():
leaf = self.add_root(self.Item(k,v))
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p.key() == k:
p.element().value = v
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
item = self.Item(k,v)
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ p.key() < k:
leaf = self.addright(p,item)
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
leaf = self.add_left(p,item)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">iter@H40417@<span class="hljs-params">(self)@H40417@:@H40417@
p = self.first()
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ p <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
<span class="hljs-keyword" style="font-weight: bold;">yield@H404_17@ p.key()
p = self.after(p)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">mapdelete@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.left(p) <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ self.right(p): <span class="hljs-comment" style="color: #738191;">#两个孩子都有的时候@H404_17@
replacement = self._subtree_lastposition(self.left(p)) <span class="hljs-comment" style="color: #738191;">#用左子树最右位置代替@H404_17@
self.replace(p,replacement.element())
p = replacement
self.delete(p)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">delitem@H40417@<span class="hljs-params">(self,k)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H404_17@ self.is_empty():
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ k == p.key():
self.mapdelete(p)
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@
<span class="hljs-keyword" style="font-weight: bold;">raise@H40417@ KeyError(<span class="hljs-string" style="color: #0048ab;">'Key Error'@H404_17@ + repr(k))
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">setitem@H40417@<span class="hljs-params">(self,k,v)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.is_empty():
leaf = self.add_root(self.Item(k,v))
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p.key() == k:
p.element().value = v
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
item = self.Item(k,v)
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ p.key() < k:
leaf = self.addright(p,item)
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
leaf = self.add_left(p,item)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">iter@H40417@<span class="hljs-params">(self)@H40417@:@H40417@
p = self.first()
<span class="hljs-keyword" style="font-weight: bold;">while@H40417@ p <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@:
<span class="hljs-keyword" style="font-weight: bold;">yield@H404_17@ p.key()
p = self.after(p)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">mapdelete@H40417@<span class="hljs-params">(self,p)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ self.left(p) <span class="hljs-keyword" style="font-weight: bold;">and@H40417@ self.right(p): <span class="hljs-comment" style="color: #738191;">#两个孩子都有的时候@H404_17@
replacement = self._subtree_lastposition(self.left(p)) <span class="hljs-comment" style="color: #738191;">#用左子树最右位置代替@H404_17@
self.replace(p,replacement.element())
p = replacement
self.delete(p)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_40417@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">delitem@H40417@<span class="hljs-params">(self,k)@H40417@:@H40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H404_17@ self.is_empty():
p = self._subtreesearch(self.root(),k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ k == p.key():
self.mapdelete(p)
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@
<span class="hljs-keyword" style="font-weight: bold;">raise@H40417@ KeyError(<span class="hljs-string" style="color: #0048ab;">'Key Error'@H404_17@ + repr(k))
404_17@ 404_17@404_17@:@H_404_17@ 元组"""@H_404_17@ 404_17@ self.is_empty(): 404_17@ 404_17@ 404_17@: p = self.first() 404_17@(p.key(),p.value())
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findge@H40417@<span class="hljs-params">(self,k)@H40417@:@H404_17@
<span class="hljs-string" style="color: #0048ab;">"""找第一个大于等于k的键值元组"""@H_40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.isempty():
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self.findposition(k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p.key() < k:
p = self.after(p)
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ (p.key(),p.value()) <span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">else@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H404_17@<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findrange@H40417@<span class="hljs-params">(self,start,stop)@H40417@:@H404_17@
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">not@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ self.is_empty(): <span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ start <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@: p = self.first() <span class="hljs-keyword" style="font-weight: bold;">else@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@: p = self.find_position(start) <span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p.key() < start: p = self.after(p) <span class="hljs-keyword" style="font-weight: bold;">while@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">not@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">and@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ (stop <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">or@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p.key() < stop): <span class="hljs-keyword" style="font-weight: bold;">yield@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ (p.key(),p.value()) p = self.after(p)
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">not@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ self.is_empty():
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ start <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@:
p = self.first()
<span class="hljs-keyword" style="font-weight: bold;">else@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@:
p = self.find_position(start)
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p.key() < start:
p = self.after(p)
<span class="hljs-keyword" style="font-weight: bold;">while@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">not@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">and@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ (stop <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">or@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p.key() < stop):
<span class="hljs-keyword" style="font-weight: bold;">yield@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ (p.key(),p.value())
p = self.after(p)
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findge@H40417@<span class="hljs-params">(self,k)@H40417@:@H404_17@
<span class="hljs-string" style="color: #0048ab;">"""找第一个大于等于k的键值元组"""@H_40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.isempty():
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self.findposition(k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p.key() < k:
p = self.after(p)
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ (p.key(),p.value()) <span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">else@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H404_17@
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findrange@H40417@<span class="hljs-params">(self,start,stop)@H40417@:@H404_17@
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findge@H40417@<span class="hljs-params">(self,k)@H40417@:@H404_17@
<span class="hljs-string" style="color: #0048ab;">"""找第一个大于等于k的键值元组"""@H_40417@
<span class="hljs-keyword" style="font-weight: bold;">if@H404_17@ self.isempty():
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@
<span class="hljs-keyword" style="font-weight: bold;">else@H404_17@:
p = self.findposition(k)
<span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p.key() < k:
p = self.after(p)
<span class="hljs-keyword" style="font-weight: bold;">return@H40417@ (p.key(),p.value()) <span class="hljs-keyword" style="font-weight: bold;">if@H40417@ p <span class="hljs-keyword" style="font-weight: bold;">is@H40417@ <span class="hljs-keyword" style="font-weight: bold;">not@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H40417@ <span class="hljs-keyword" style="font-weight: bold;">else@H40417@ <span class="hljs-keyword" style="font-weight: bold;">None@H404_17@
<span class="hljs-function"><span class="hljs-keyword" style="font-weight: bold;">def@H_404_17@ <span class="hljs-title" style="font-weight: bold; color: #0048ab;">findrange@H40417@<span class="hljs-params">(self,start,stop)@H40417@:@H404_17@
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">not@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ self.is_empty():
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ start <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@:
p = self.first()
<span class="hljs-keyword" style="font-weight: bold;">else@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@:
p = self.find_position(start)
<span class="hljs-keyword" style="font-weight: bold;">if@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p.key() < start:
p = self.after(p)
<span class="hljs-keyword" style="font-weight: bold;">while@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">not@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">and@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ (stop <span class="hljs-keyword" style="font-weight: bold;">is@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">None@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ <span class="hljs-keyword" style="font-weight: bold;">or@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ p.key() < stop):
<span class="hljs-keyword" style="font-weight: bold;">yield@H_<a href="https://www.jb51.cc/tag/404/" target="_blank" class="keywords">404</a>_17@ (p.key(),p.value())
p = self.after(p)
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