112.js

/** ------------------------------------------------------------------------------
 * 
 * 112. Path Sum
 * Topics: Tree, Depth-First Search, Binary Tree
 * https://leetcode.com/problems/path-sum/description/
 * 
 ------------------------------------------------------------------------------ */
/**
 * 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} root
 * @param {number} targetSum
 * @return {boolean}
 */
var hasPathSum = function (root, targetSum) {
  if (!root) return false
  if (!root.left && !root.right && targetSum === root.val) return true

  return hasPathSum(root.left, targetSum - root.val) || hasPathSum(root.right, targetSum - root.val)
}

var hasPathSumBFS = function (root, targetSum) {
  if (!root) return false
  const queue = [[root, root.val]]

  while (queue.length) {
    const [node, sum] = queue.shift()
    if (!node.left && !node.right && sum === targetSum) return true
    if (node.left) queue.push([node.left, sum + node.left.val])
    if (node.right) queue.push([node.right, sum + node.right.val])
  }

  return false
}

console.log(hasPathSum([5, 4, 8, 11, null, 13, 4, 7, 2, null, null, null, 1], 22))
console.log(hasPathSumBFS([5, 4, 8, 11, null, 13, 4, 7, 2, null, null, null, 1], 22))