java--二分法

class Demo{

public static void main(String[] args){

//二分法：前提：数组要排序好

int[] arr = {1,2,3,4,5,6};

int num = 5;

int max = arr.length-1;

int min = 0;

int mid = (max + min ) / 2;

while(true){

if(num > arr[mid]){

min = mid + 1;

}else if(num < arr[mid]){

max = mid-1;

}else {

System.out.println("找到了:"+mid);

break;

}

//没有找到

if(mid > max){

System.out.println("没有找到");

break;

}

//重新设置中间值

mid = (max + min) / 2;

}

}

}