Skip to main content

Same Tree

Problem statement​

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

My solution​

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} p
 * @param {TreeNode} q
 * @return {boolean}
 */
var isSameTree = function(p, q) {
    function dfs(node1, node2) {
        if (!node1 && !node2) {
            return true;
        }
        if (!node1 || !node2) {
            return false;
        }
        
        if (node1.val === node2.val) {
            return dfs(node1.left, node2.left) && dfs(node1.right, node2.right)
        } else{
            return false
        }
    }
    
    return dfs(p, q)
};