Java-二分法查找

package com.it;

import java.util.Arrays;

/**
 * 测试二分法查找
 */
public class Test08 {
    public static void main(String[] args) {
        int[] arr = {22,42,11,44,87,33,43,54};
        int searchValue = 44;//要查找的值
        System.out.println(searchValue+"索引位置："+binarySearch(arr,searchValue));
    }

    /**
     *
     * @param array 目标数组
     * @param value 索要查找的值
     * @return 如果找到，则返回这个值在数组中的索引，没找到则返回-1
     */
    public static int binarySearch(int[] array,int value) {
        Arrays.sort(array);//对数组进行排序
//        System.out.println(Arrays.toString(array));
        int low = 0;//数组最小值下标
        int high = array.length-1;//数组最大值下标
        while (low<=high) {
            int middle = (low+high)/2;
            if(value == array[middle]) {
                return middle;
            }
            if(value<array[middle]) {
                high = middle-1;
            }
            if(value>array[middle]) {
                low = middle+1;
            }
        }
        return -1;//如果没找到则返回-1
    }
}