【Leetcode】100. Same Tree（检测两棵二叉树是否相同）

╰+哭是因爲堅強的太久メ 2022-04-24 03:32 202阅读 0赞

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

/**
     * 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 {
    private:
        bool valid(TreeNode* p, TreeNode* q){
            
            if(p==NULL&&q==NULL){
                return true;
            }else if(p!=NULL&&q!=NULL){
                if(p->val!=q->val){
                    return false;
                }else{
                    return (valid(p->left, q->left)&&valid(p->right, q->right));
                }
            }else{
                return false;
            }    
        }
    public:
        bool isSameTree(TreeNode* p, TreeNode* q) {
            if(p!=NULL&&q!=NULL){
                return valid(p,q);
            }
            else if (p==NULL&&q==NULL){
                return true;
            }
            else{
                return false;
            }
        }
    };