// recursive solution: time complexity: O(n) | space complexity: O(h) where h is height of tree (recursion stack) var isSameTree = function (p, q) { if (!p && !q) { return true; } if (!p || !q || p.val !== q.val) { return false; } return isSameTree(p.left, q.left) && isSameTree(p.right, q.right); };