二叉树，给定任意两个节点，寻找最近的父节点

网上看到的一个题目： 给定一棵二叉树，以及两个节点，请找出它们最近的父节点。

所谓最近，就是“血缘关系”最近啦，这个你懂得~~

用python写了一下，感觉还不坏：



class node:
[align=left] def __init__( self , data, left, right):[/align]
[align=left] self .data = data[/align]
[align=left] self .left = left[/align]
[align=left] self .right = right[/align]
[align=left] [/align]
[align=left]def is_leaf(n):[/align]
[align=left] if n.left == None and n.right == None:[/align]
[align=left] return True[/align]
[align=left] return False[/align]
[align=left] [/align]
[align=left]def find_parent(n, data1, data2):[/align]
[align=left] if n == None :[/align]
[align=left] return 0[/align]
[align=left] [/align]
[align=left] if is_leaf(n):[/align]
[align=left] if n.data == data1:[/align]
[align=left] return 1[/align]
[align=left] elif n.data == data2:[/align]
[align=left] return 2[/align]
[align=left] else :[/align]
[align=left] return 0[/align]
[align=left] [/align]
[align=left] lr = find_parent(n.left, data1, data2)[/align]
[align=left] rr = find_parent(n.right, data1, data2)[/align]
[align=left] [/align]
[align=left] if lr + rr == 3:[/align]
[align=left] print "find node : " + str(n.data)[/align]
[align=left] [/align]
[align=left] return lr + rr[/align]
[align=left] [/align]
[align=left]def print_tree(t):[/align]
[align=left] if t == None :[/align]
[align=left] return[/align]
[align=left] [/align]
[align=left] print t.data[/align]
[align=left] print_tree(t.left)[/align]
[align=left] print_tree(t.right)[/align]
[align=left] [/align]
[align=left]tree = node(1, None, None )[/align]
[align=left]tree.left = node(2, None, None )[/align]
[align=left]tree.right = node(3, None, None )[/align]
[align=left]tree.left.left = node(4, None, None )[/align]
[align=left]tree.left.right = node(5, None, None )[/align]
[align=left]tree.left.left.left = node(6, None, None )[/align]
[align=left]tree.left.left.right = node(7, None, None )[/align]
[align=left]tree.right.left = node(8, None, None )[/align]
[align=left]tree.right.right = node(9, None, None )[/align]
[align=left] [/align]
[align=left]print_tree(tree)[/align]
[align=left]print "------------------"[/align]
[align=left]find_parent(tree, 7, 6)[/align]
[align=left]print "------------------"[/align]
[align=left]find_parent(tree, 7, 5)[/align]