【DataStructure In Python】Python模拟二叉树
使用Python模拟二叉树的基本操作,感觉写起来很别扭。最近做编译的优化,觉得拓扑排序这种东西比较强多。近期刷ACM,发现STL不会用实在太伤了。决定花点儿时间学习一下STL。Boost其实也很强大。关于Python最近没什么时间搞了,忙着复试了。不过,挺喜欢这语言的。复试完继续大战PythonChallenge。
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1 #! /usr/bin/env python 2 # DataStrucure Tree 3 4 import sys 5 6 class BTNode: 7 8 def __init__(self, data, lchild=None, rchild=None): 9 self.data = data 10 self.lchild = lchild 11 self.rchild = rchild 12 13 def __str__(self): 14 print "root: %s lchild: %s rchild: %s" % (data, lchild.data, rchild.data) 15 16 17 class BTree: 18 19 def __init__(self, data=None, ldata=None, rdata=None): 20 self.root = BTNode(data) 21 self.root.lchild = BTNode(ldata) 22 self.root.rchild = BTNode(rdata) 23 24 def isEmpty(self): 25 if self.root.data is None: 26 return 1 27 else: 28 return 0 29 30 31 def findNode(self, data): 32 lst = [] 33 if self.isEmpty(): 34 print "The tree is empty." 35 return None 36 lst.append(self.root) 37 while len(lst): 38 BTemp = lst.pop(0) 39 if BTemp.data == data: 40 return BTemp 41 if BTemp.lchild is not None: 42 lst.append(BTemp.lchild) 43 if BTemp.rchild is not None: 44 lst.append(BTemp.rchild) 45 return None 46 47 def addchilds(self, data, ldata=None, rdata=None): 48 BTemp = self.findNode(data) 49 if BTemp is None: 50 print "Can't find Node: %s" % data 51 return 0 52 else: 53 BTemp.lchild = None if ldata is None else BTNode(ldata) 54 BTemp.rchild = None if rdata is None else BTNode(rdata) 55 return 1 56 57 def levelorder(self): 58 if self.isEmpty(): 59 print "Root is not initialized." 60 return 61 lst = [] 62 lst.append(self.root) 63 while len(lst): 64 BTemp = lst.pop(0) 65 print "-> %s" % BTemp.data, 66 if BTemp.lchild is not None: 67 lst.append(BTemp.lchild) 68 if BTemp.rchild is not None: 69 lst.append(BTemp.rchild) 70 71 def preorder(self, Node): 72 if Node is not None: 73 print "-> %s" % Node.data, 74 self.preorder(Node.lchild) 75 self.preorder(Node.rchild) 76 77 def inorder(self, Node): 78 if Node is not None: 79 self.inorder(Node.lchild) 80 print "-> %s" % Node.data, 81 self.inorder(Node.rchild) 82 83 def postorder(self, Node): 84 if Node is not None: 85 self.postorder(Node.lchild) 86 self.postorder(Node.rchild) 87 print "-> %s" % Node.data, 88 89 def __str__(self): 90 if self.isEmpty(): 91 print "Root is not initialized." 92 return None 93 tmp = "" 94 lst = [] 95 lst.append(self.root) 96 while len(lst): 97 BTemp = lst.pop(0) 98 tmp += ("-> %s " % BTemp.data) 99 if BTemp.lchild is not None: 100 lst.append(BTemp.lchild) 101 if BTemp.rchild is not None: 102 lst.append(BTemp.rchild) 103 return tmp 104 105 if __name__ == "__main__": 106 tree = BTree('A') 107 tree.addchilds('A','B','C') 108 tree.addchilds('B','D','E') 109 tree.addchilds('C','F', None) 110 print "\n","-"*5," Find ","-"*5 111 tmp = tree.findNode('B') 112 if tmp is not None: 113 print "Found 'B', lchild is %s, rchild is %s." % (tmp.lchild.data, tmp.rchild.data) 114 else: 115 print "Not found 'B'." 116 print "\n","-"*5," Preorder ","-"*5 117 tree.preorder(tree.root) 118 print "\n\n","-"*5," Inorder ","-"*5 119 tree.inorder(tree.root) 120 print "\n\n","-"*5," Postorder ","-"*5 121 tree.postorder(tree.root) 122 print "\n\n","-"*5," Lvlorder ","-"*5 123 tree.levelorder() 124 print "\n\n"