leetcode100

最新推荐文章于 2025-01-01 11:47:31 发布

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100. Same Tree

Description：

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

Example 1:

Input:     1         1
          / \       / \
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1
          /           \
         2             2

        [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1
          / \       / \
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false

思路：递归的方法，若p和q均为NULL则返回true，当都不为NULL时，判断节点值是否相等，若不相等返回false，若相等则判断当前节点的左右子节点，其他情况：当前判断的两个节点只有一个为NULL时返回false。

代码如下：

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