Home > Article > Backend Development > Python implements binary search tree
# -*- coding: cp936 -*- #--------------------------------------------- # # author chile # version 1.0 # date 2014-02-17 # desc 二叉树 # # # #--------------------------------------------- class bintree: def __init__(self): self.root = None # 前驱节点 def treePredecessor(self,entry): if entry.left != None: return self.maxTree(entry.left) preNode = entry.parent tempNode = entry while preNode != None and preNode.right.value != entry.value: tempNode = preNode preNode = preNode.parent return preNode #后继节点 def treeSuccessor(self,entry): if entry.right != None: return self.minTree(entry.right) preNode = entry.parent tempNode = entry while preNode != None and preNode.left.value != entry.value: tempNode = preNode preNode = preNode.parent return preNode def add(self,value): tempNode = self.root parentNode = None entry = bintree.entry(value = value) while tempNode != None: parentNode = tempNode if cmp(value,parentNode.value) < 0: tempNode = tempNode.left else: tempNode = tempNode.right if parentNode == None: self.root = entry elif cmp(value,parentNode.value) < 0: parentNode.left = entry entry.parent = parentNode else: parentNode.right = entry entry.parent = parentNode #这里删除是全部删除节点(包括所有子节点) def remove(self,value): root = self.root parentNode = None if value == root.value: root.left = None root.right = None while root != None: parentNode = root.parent if value == root.value: root.left = None root.right = None if parentNode.left != None and parentNode.left.value == value: parentNode.left = None break else: parentNode.right = None break elif cmp(value,root.value) < 0: root = root.left else: root = root.right #查找节点 def search(self,value): root = self.root while root != None and root.value != value: if cmp(value,root.value) < 0: root = root.left else: root = root.right return root #最小值的节点,其实就是找左边的叶子节点 def minTree(self,root): entry = root while entry.left != None: entry = entry.left return entry #最大值的节点 def maxTree(self,root): entry = root while entry.right != None: entry = entry.right return entry #中序遍历 def iterator(self,root): if root != None: self.iterator(root.left) print root.value self.iterator(root.right) class entry: def __init__(self, value=None): self.left = None self.right = None self.parent = None self.value = value arr = [15,5,3,12,10,13,6,7,16,20,18,23] tree = bintree() for val in arr: tree.add(val) tree.iterator(tree.root) node = tree.search(16) print node.left , node.right , node.parent.value print tree.maxTree(node).value print tree.treePredecessor(node).value print tree.treeSuccessor(node).value #print tree.maxTree() , tree.minTree()