二分查找（Java）

import java.util.Arrays;

public class FindingTwo {
    public static void main(String[] args) {
        //二分查找
        int[] number = new int[]{1, 2, 32, 12,16,19,24,67,46};
        Arrays.sort(number);
        System.out.println(Arrays.toString(number));
        System.out.println(binarySearch(number,13));
    }

    public static int binarySearch(int[] number, int data) {//升序版
        int left = 0;
        int right = number.length - 1;
        int middle = 0;
        while (left <= right) {
            middle = (left + right) / 2;
            if (number[middle] < data) {
                left = middle + 1;
            } else if (number[middle] > data) {
                right = middle - 1;
            }else{
                //这里就是找到的情况
                return middle;
            }
        }
        //没找到的话返回middle+1
        return -(left+1);//返回的是想要找的数字在数组索引位置的负数减一
    }
}