max score with one reset

main.js

// Given an array of numbers, sums the element in order. The sum is reset
// exactly once during this process. The function returns the maximum sum.
function maxScore(arr) {
  let sum = 0;
  let max = arr[arr.length - 1];

  // for exactly one reset, i > 0
  // for at most one reset, i >= 0
  for (let i = arr.length - 1; i > 0; i--) {
    sum += arr[i];
    arr[i] = sum;
    max = Math.max(max, sum);
  }

  return Math.max(max, 0);
}