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Subarray of another tree

Tags : tree, leetcode, cpp, easy

Problem Statement - link #

Given the roots of two binary trees root and subRoot, return true if there is a subtree of root with the same structure and node values of subRoot and false otherwise.

A subtree of a binary tree tree is a tree that consists of a node in tree and all of this node’s descendants. The tree tree could also be considered as a subtree of itself.

Examples #

Example 1:

Input: root = [3,4,5,1,2], subRoot = [4,1,2]
Output: true

Example 2: 

Input: root = [3,4,5,1,2,null,null,null,null,0], subRoot = [4,1,2]
Output: false

Constraints #

Solutions #

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    
    bool check(TreeNode* root, TreeNode* subRoot){
        
        if(!root and !subRoot) return true;
        if(!root or !subRoot or root->val != subRoot->val) return false;
        return check(root->left,subRoot->left) and check(root->right,subRoot->right);
        
    }
    
    bool isSubtree(TreeNode* root, TreeNode* subRoot) {
        
        if(!root) return false;
        if(root->val == subRoot->val and check(root,subRoot)) return true;
        return isSubtree(root->left, subRoot) or isSubtree(root->right, subRoot);
        
    }
    
};