257. Binary Tree Paths

https://leetcode.com/problems/binary-tree-paths/

Python

Javascript

var binaryTreePaths = function(root) {
  var result = [];
  
  var backtrack = function(node, n = []) {
    if (node) {
      n.push(node.val)
      
      if (node.left === null && node.right === null) {
        result.push(n.join('->'))
      } else {
        backtrack(node.left, n.slice(0));  
        backtrack(node.right, n.slice(0)); 
      }
    }
  }

  backtrack(root);
  return result;
};