算法：二分法查找

package com.atguigu;public class Main {    public static void main(String[] args) {        //二分法查找        //前提：所查找的数组必须有序        int[] arr=new int[]{-98,-34,2,34,54,66,79,105,210,333};        int dest=-3;        int head=0;//初始的首索引        int end=arr.length-1;                boolean isFlag=true;        while(head<=end){            int middle=(head+end)/2;            if(dest==arr[middle]){                System.out.println("找到指定的元素，位置为"+middle);                isFlag=false;                break;            }else if(arr[middle]>dest){                end=middle-1;            }else{                head=middle+1;            }        }        if(isFlag){            System.out.println("很遗憾，没有找到");        }    }}

来源：https://www.cnblogs.com/helloworld0903/p/11456552.html