Same Tree

问题描述：

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.

解决思路：DFS遍历两颗二叉树的结点，只要有一个不同就返回false

/**
 * 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 == NULL)
        {
            if (q == NULL)
                return true;
            return false;
        }
        if(q == NULL)
        {
            if (p == NULL)
                return true;
            return false;
        }
        if (p->val != q->val)
            return false;
        bool lsame = isSameTree(p->left,q->left);
        bool rsame = isSameTree(p->right,q->right);
        if(lsame==false||rsame==false)
            return false;
        return true;
        
    }
};