/**
 * @param {number[]} numbers
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function (numbers, target) {
  var p1 = 0
  var p2 = numbers.length - 1

  while (p1 < p2) {
    if (numbers[p1] + numbers[p2] < target) {
      p1 += 1
    } else if (numbers[p1] + numbers[p2] > target) {
      p2 -= 1
    } else {
      return [p1 + 1, p2 + 1]
    }
  }
  return [-1, -1]
}

console.log(twoSum([2, 7, 11, 15], 9))