学点儿算法 Ts版

二分查找

export function BinarySearch(key: number, arr: number[]) {  // 数组必须是有序的  let low: number = 0;  let hi: number = arr.length - 1;
  while (low <= hi) {    const mid = low + (hi - low) / 2;    if (key < arr[mid]) {      hi = mid - 1;    } else if (key > arr[mid]) {      low = mid + 1;    } else {      return mid;    }  }  return -1;}