Java二分法查找原理

package chapter_01;


public class MidSearchSort {

    public static void main(String[] args) {
        int[]  arr = {10,23,56,98,101,105,1024};
        int index = searchSort(arr,23);
        System.out.println(index == -1? "数组中没有该元素" :"数组的下标为" + index);
    }

    private static int searchSort(int[] arr, int i) {
        int begin = 0;
        int end = arr.length - 1;
        //结束的条件（开始坐标大于结束坐标）
        while (begin <= end){
			//每次从中间砍掉一半
            int mid = (begin + end) / 2;
            if(arr[mid] == i){
                return mid;
            }
            else if(arr[mid] < i){
                begin = mid + 1;
            }
            else{
                end = mid - 1;
            }
        }
        return -1;
    }
}