编辑代码

class Main {
	public static void main(String[] args) {
        int[] arr = {85, 63, 52, 34, 25, 17, 6};
        int pos = halfFind(arr,6);
        if(pos!=-1){
            System.out.println("该数存在,下标为"+ pos);
        }else{
            System.out.println("不存在");
        }
	}
    public static int halfFind(int[] arr,int target){
        int pos = -1;
        int left = 0;
        int right = arr.length-1;
        while(left<=right){
            int mid = left + ((right - left)>>1);
            if(arr[mid]<target){
                right = mid-1;
            }else if(arr[mid]>target){
                left = mid+1;
            }else{
                pos = mid;
                break;
            }
        }
        return pos;
    }
}