day-104.cpp

/*
  Same Tree


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
*/

// Simple recursive solution to tell is the given trees are same.
class Solution {
   public:
    bool isSameTree(TreeNode* p, TreeNode* q) {
        if (p == NULL && q == NULL) return true;
        if (p == NULL || q == NULL) return false;

        if (p->val != q->val) return false;

        return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
    }
};