pathToTargetSum.js

/*
Tree has path to target sum?

You are given a binary tree whose nodes all have integer values (both positive and negative).

Given some target sum (say, 14), return true if there is any path starting from the root and ending in a leaf, such that adding up all the values along the path equals the given sum.
*/
const BinaryTree = function(value) {
  this.value = value;
  this.left = null;
  this.right = null;
}

BinaryTree.prototype.insert = function(value) {
  let node = new BinaryTree(value);

  function recurs(BT) {
    if (BT.value <= value && BT.right === null) {
      BT.right = node;
    } else if (BT.value <= value) {
      recurs(BT.right);
    } else if (BT.value >= value && BT.left === null) {
      BT.left = node;
    } else if (BT.value >= value) {
      recurs(BT.left);
    }
  }
  recurs(this);
}

const hasPathToSum = function(node, targetSum) {
  // your code here
  if (targetSum === 0 && node.left === null && node.right === null) {
    return true
  } else {
    let result = false
    let subSum = targetSum - node.value
    if (subSum === 0 && node.left === null && node.right === null) {
      return true;
    } else if (node.left !== null) {
      result = result || hasPathToSum(node.left, subSum);
    } else if (node.right !== null) {
      result = result || hasPathToSum(node.right, subSum);
    }
    return result
  }
};

let newTree = new BinaryTree(6);
newTree.insert(1)
newTree.insert(2)
newTree.insert(2)
  // console.log(newTree);
console.log(hasPathToSum(newTree, 9))