Identical Binary Trees

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.

Return 0 / 1 ( 0 for false, 1 for true ) for this problem

Input : 

   1       1
  / \     / \
 2   3   2   3

Output : 
  1 or True

Method:

DFS

Solution:

Time: O(n)
Space: O(1)

/**
 * Definition for binary tree
 * class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) {
 *      val = x;
 *      left=null;
 *      right=null;
 *     }
 * }
 */
public class Solution {
    public int isSameTree(TreeNode A, TreeNode B) {
        if (A == null && B == null) {
            return 1;
        }
        if (A == null || B == null) {
            return 0;
        }
        if (A.val != B.val) {
            return 0;
        }
        return Math.min(isSameTree(A.left, B.left), isSameTree(A.right, B.right));
    }
}