[Leetcode]-Same Tree

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.

Hide Tags ：Tree 。Depth-first Search
题目：推断两棵二叉树是否全然同样，包含深度，节点值
思路：递归依次推断节点的左右儿子的值是否相等

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
bool isSameTree(struct TreeNode* p, struct TreeNode* q) {
    if(p == NULL && q == NULL) 
        return true;
    if(p != NULL && q == NULL) 
        return false;
    if(p == NULL && q != NULL) 
        return false;
    if(p->val != q->val)
        return false;
    return isSameTree(p->left,q->left) && isSameTree(p->right,q->right);
}