题目描述: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.
分析:本题题意是给出两个二叉树,要求写出一个函数检查这两个二叉树从结构上和节点值是否相等。
代码实现:
/**
* 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) {
//如果两棵树都为空,则这两棵树相等
if (p == NULL && q == NULL) { return p == q; }
//结构不同
else if (p == NULL || q == NULL) { return false; }
//如果二叉树节点对应的值不同,则这两棵树不相等
else if (p->val != q->val) { return false; }
return isSameTree(p->left, q->left)
&& isSameTree(p->right, q->right);
}
};