All Tests Pass: Week 1

week_1.js

/**
 * All Tests Pass: Week 1
 * Given an array of integers, find out if any two items in the array add up to
 * the target. For example, sumsToTarget([1,2], 3) should return true, but
 * sumsToTarget([1,2], 4) should return false.
 */

function sumsToTarget(integers = [], target) {
  return sumHelper(integers.sort(), target, 0, integers.length - 1);
}

function sumHelper(sortedArray, target, start, end) {
  if (end <= start) {
    // All possibilities are covered
    return false;
  } else {
    // Sum beginning and end of search area
    var sum = sortedArray[start] + sortedArray[end];
    if (sum == target){
      // Return true if sum is the target
      return true;
    } else if(sum >= target) {
      // Eliminate largest number if sum is too big
      return sumHelper(sortedArray, target, start, end - 1);
    } else {
      // Eliminate smallest number if sum is too small
      return sumHelper(sortedArray, target, start + 1, end);
    }
  }
}

// Tests: Don't edit anything after this line.

assertEqual(sumsToTarget([1, 5, 3], 3), false, "Array [1, 5, 3] does not have items that add up to 3");
assertEqual(sumsToTarget([0, 2, 3, 5, 8], 3), true, "Array [0, 2, 3, 5, 8] has items that add up to 3");
assertEqual(sumsToTarget([5, 5], 5), false, "[5, 5] does not have items that add up to 5");

console.log("All clear 🎉");

function assertEqual(first, second, output) {
  try {
    if (first !== second) {
      throw `${output} ${first} ${second}`
    }
  } catch (e) {
    throw `${e} - ${output} ${first} ${second}`
  }
}