java实现
public int binarySearch(int[] arr, int target) { int left = 0; int right = arr.length - 1; while (left <= right) { int mid = (left + right) / 2; if (arr[mid] == target) { return mid; } else if (arr[mid] < target) { left = mid + 1; } else if (arr[mid] > target) { right = mid - 1; } } return -1; }