Path Sum II

Description

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

Note: A leaf is a node with no children.

Example:

Given the below binary tree and sum = 22,

      5
     / \
    4   8
   /   / \
  11  13  4
 /  \    / \
7    2  5   1

Return:

[
   [5,4,11,2],
   [5,8,4,5]
]

Solution(javascript)

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @param {number} sum
 * @return {boolean}
 */
const pathSum = (root, sum) => {
  const res = []
  const aux = (node, currentSum, acc) => {
    if (!node) {
      return
    }
    if (node && !node.left && !node.right) {
      if ((currentSum + node.val) === sum) {
        acc.push(node.val)
        res.push(acc)
      }
    }
    
    aux(node.left, currentSum + node.val, [...acc, node.val])
    aux(node.right, currentSum + node.val, [...acc, node.val])
  }
  if (root === null) {
    return res
  }
  aux(root, 0, [])
    return res
}