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.
判断两棵树是否相同和之前的判断两棵树是否对称都是一样的原理，利用深度优先搜索DFS来递归。代码如下：
/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: bool isSameTree(TreeNode *p, TreeNode *q) { if (!p && !q) return true; if ((p && !q) || (!p && q) || (p->val != q->val)) return false; return isSameTree(p->left, q->left) && isSameTree(p->right, q->right); } };
原文：http://www.cnblogs.com/grandyang/p/4053384.html