End of Array Reachable

function arrayReachableEnd(numbers: number[]): boolean {
  const n = numbers.length;
  let sum = 0;

  if (numbers[0] === 0) return false;

  for (const num of numbers) {
    sum += num;
  }

  return sum >= n;
}

function canJump(numbers: number[]): boolean {
  let maxReach = 0;

  for (let i = 0; i < numbers.length; i++) {
    if (i > maxReach) return false;
    maxReach = Math.max(maxReach, i + numbers[i]);
  }

  return true;
}