二分法查找介绍+代码

package com.qf.com.qf.weekend;
/*
 * zt
 * 2020/7/25
 * 10:05
 *
 */

import java.util.Arrays;

public class Demo2 {
    public static void main(String[] args) {
        int[] arr = {50,20,80,10,60,30};
        Arrays.sort(arr);
        System.out.println(Arrays.toString(arr));
        int num = midSearch(arr,80);
        System.out.println(num);
    }
    //二分法查找
    public static int midSearch(int[] arr, int num){
        int low = 0;
        int upper = arr.length-1;
        while (low <= upper) {
            int mid = (low + upper)>>>1;
            if(arr[mid]>num){
                upper = mid - 1;
            }else if(arr[mid]<num){
                low = mid + 1;
            }else{
                return mid;
            }
        }
        return -1;
    }
}