[题目]
Given two binary trees, write a function to check if they are equal or not.
Two binary trees are considered equal if they are structurally identical and the nodes have the same value.
[题目解析] 二叉树的问题，转化成当前节点与左子树，右子树问题。注意一些临界条件的判断。
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { public boolean isSameTree(TreeNode p, TreeNode q) { if(null == p && null == q) return true; if(null != p && null != q){ return (p.val == q.val && isSameTree(p.left,q.left) && isSameTree(p.right,q.right)); }else{ return false; } } }
原文：http://www.cnblogs.com/zzchit/p/5778166.html