演算法：二分法查找

package com.atguigu;

public class Main {
    public static void main(String[] args) {
        //二分法查找
        //前提：所查找的數組必須有序
        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，位置為"+middle);
                isFlag=false;
                break;
            }else if(arr[middle]>dest){
                end=middle-1;
            }else{
                head=middle+1;
            }
        }
        if(isFlag){
            System.out.println("很遺憾，沒有找到");
        }

    }
}