Construct Target Array With Multiple Sums LeetCode solution in JavaScript

1
var isPossible = function (target) {
2
  let max = 0;
3
  let index = -1;
4

5
  for (let i = target.length - 1; i >= 0; i--) {
6
    if (target[i] > max) {
7
      max = target[i];
8
      index = i;
9
    }
10
  }
11
  if (max === 1) return true; // if max itself is 1 return true
12

13
  let total = 0;
14
  for (let i = 0; i < target.length; i++) {
15
    if (i !== index) {
16
      total += target[i];
17
    }
18
  }
19
  // If total=1,it means only one element was remaining apart from max and its value is 1 return true
20
  // eg target=[10,1] we started with [1,1] so next steps would be [2,1]->[3,1]->...[10,1] we can make sure it leads to target
21
  if (total === 1) return true;
22
  // max should be greater than remaining nums sum OR if total is 0 it would lead to infinite loop( num%0 === NaN) so return false
23
  if (max <= total || total === 0) return false;
24
  max = max % total;
25
  if (max < 1) return false; // it should not be less than 1
26
  target[index] = max;
27

28
  return isPossible(target);
29
};