100. Same Tree.cpp

/*
Given the roots of two binary trees p and q, 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: p = [1,2,3], q = [1,2,3]
Output: true

Example 2:
Input: p = [1,2], q = [1,null,2]
Output: false

Example 3:
Input: p = [1,2,1], q = [1,1,2]
Output: false

Constraints:
The number of nodes in both trees is in the range [0, 100].
-104 <= Node.val <= 104
*/

/**
 * 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) {}
 * };
 */

// Elaborated Solution

class Solution {
public:
    bool check(TreeNode* p, TreeNode* q){
        if (!p && !q)
            return true;
        if (p && q){
            bool leftAns = check(p -> left, q -> left);
            bool rightAns = check(p -> right, q -> right);
            bool rootAns = p -> val == q -> val;
            return leftAns && rightAns && rootAns;
        }
        return false;
    }
    
    bool isSameTree(TreeNode* p, TreeNode* q) {
        if (check(p, q))
            return true;
        return false;
    }
};

// Smaller Solution

class Solution {
public:
    bool isSameTree(TreeNode* p, TreeNode* q) {
        if (!p && !q)
            return true;
        if (p && q){
            bool ans = isSameTree(p -> left, q -> left) && isSameTree(p -> right, q -> right);
            if (p -> val == q -> val)
                return true && ans;
        }
        return false;
    }
};