package cn.ljm.arrays;

/**
 * 测试二分法查找（折半查找）
 * @author LJM
 */

import java.util.Arrays;

public class TestBinarySearch {

    public static void main(String[] args) {
        int [] array = {30, 20, 50, 10, 80, 9, 7, 12, 100, 40, 8};
        Arrays.sort(array);//先排序
        System.out.println(Arrays.toString(array));
        System.out.println(binarySearch(array, 40));
    }

    //二分查找
    public static int binarySearch(int [] array, int value) {
        int low = 0;
        int hight = array.length - 1;
        while(low <= hight) {
            int mid = (low + hight) / 2;
            if(array[mid] == value) return mid;
            else if(value < array[mid]) hight = mid - 1;
            else low = mid + 1;
        }
        return -1;
    }

}