LeetCode——same-tree

Question

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.

Solution

递归判断，首先要判断结构是否一样，如果不一样直接返回false，如果结构一样，那么要继续判断值是否相等，如果不等直接返回false，如果相等，那么继续遍历左子树和右子树。

Code

/**
* 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 && q == NULL)
return true;
if (p == NULL)
return false;
if (q == NULL)
return false;
if (p->val == q->val) {
return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
} else
return false;
}
};