LeetCode:Same Tree

Posted 2020-07-21 walker lee

Same Tree

Total Accepted: 132356 Total Submissions: 304237 Difficulty: Easy

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.

Subscribe to see which companies asked this question

Hide Tags

 Tree Depth-first Search

c++ code:

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
bool isSam;
/*
void preOrder(TreeNode* p, TreeNode* q)
{
    if(!isSam) return;
    if(NULL == p && NULL == q) return;
    if(NULL == p && NULL!= q || NULL != p && NULL== q) 
    {
        isSam = false;
        return;
    }
    if(p->val != q->val)
    {
        isSam = false;
        return;
    }
    preOrder(p->left, q->left);
    preOrder(p->right, q->right);
}
*/
void inOrder(TreeNode* p, TreeNode* q)
{
    if(!isSam) return;
    if(NULL == p && NULL == q) return;
    if(NULL == p && NULL!= q || NULL != p && NULL== q) 
    {
        isSam = false;
        return;
    }
    inOrder(p->left, q->left);
    if(p->val != q->val)
    {
        isSam = false;
        return;
    }
    inOrder(p->right, q->right);
}


class Solution {
public:
    bool isSameTree(TreeNode* p, TreeNode* q) {
        isSam = true;
        //preOrder(p,q);
        inOrder(p,q);
        return isSam;
    }
};