aug_31.js

function maxSubarray(arr, k) {
  if (arr.length < k) return 0
  let currSubSum = arr.slice(0, k).reduce((a, b) => a + b);
  let sum = currSubSum;
  for (let i = k; i < arr.length; i++) {
    currSubSum = currSubSum + arr[i] - arr[i - k]
    sum = Math.max(sum, currSubSum)
  }
  return sum
}

console.log(maxSubarray([100, 200, 300, 400], 2));
console.log(maxSubarray([1, 2, -1, 4, -8, 2], 3));

function getLeaders(arr) {
  let rightMax = 0;
  const res = [];
  for (let i = arr.length - 1; i >= 0; i--) {
    if (arr[i] > rightMax) {
      rightMax = arr[i]
      res.unshift(rightMax)
    }
  }
  return res
}

console.log(getLeaders([8, 1, 3, 4, 2]))
console.log(getLeaders([16, 17, 4, 3, 5, 2]))