Minimum Penalty for a Shop

export function bestClosingTime(customers: string): number {
  const n = customers.length;
 
  let minPenalty = 0;
  let currentPenalty = 0;
  let earliestTime = 0;
  for (let i = 0; i < n; i++) {
    currentPenalty += customers[i] === 'N' ? 1 : -1;
    if (currentPenalty < minPenalty) {
      minPenalty = currentPenalty;
      earliestTime = i + 1;
    }
  }
 
  return earliestTime;
}