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.

 判断两颗树是否相等。

思路：定义一个函数,判断两颗树是否都为空，如果都为空则返回true，其他情况都返回false，不断递归这两颗树的坐子树和右子树。根据返回的结果判断两颗树是否相等。

 

代码如下：

/**
 * 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->val!=q->val) return false;
    
    return isSameTree(p->left, q->left)&&isSameTree(p->right, q->right);  //递归调用函数
}