二分查找Java实现

public class Search {

    public static void main(String[] args) {

        int[] arr = {12,16,30,45,63,79};
        int index = binarySearch(arr, 16);
        System.out.println(index);
    }

    public static int binarySearch(int[] arr, int target) {

        int low = 0;
        int high = arr.length - 1;
        // 注意判断条件,必须是 <=
        while(low <= high){
            // mid防止越界
            int mid = low + (high - low) / 2;
            if(arr[mid] > target){
                high = mid - 1;
            }
            else if(arr[mid] < target){
                low = mid + 1;
            }
            else{
                return mid;
            }
        }
        return -1;
    }
}