Same Tree.cpp

/*
Same Tree
=========

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) {}
 * };
 */

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