二分查找算法的两种实现

前提条件必须元素有序 ，推荐第一种

package binary;public class Test {    public static void main(String[] args) {        // int[] i = new int[]{1,4,6,8,9,11,33,44,55};        int[] i = { 3, 6, 8, 9, 11, 55, 66 };        int index = BinarySearch(i, 11);        System.out.println(index);    }    public static int BinarySearch(int[] array, int key) {        int min = 0;        int max = array.length - 1;        while (min <= max) {            int mid = (min + max) >> 1;            if (key > array[mid])                min = mid + 1;            else if (key < array[mid])                max = mid - 1;            else                return mid;//mid为所查元素下标        }        return min;//如果要查询的元素在数组中都不存在 返回要查询的的元素在数组中的位置（介于两个数下标中间）    }    public static int BinarySearch2(int[] array , int key){        int min = 0;        int max = array.length - 1;        int mid = (min + max) >> 1;        while( array[mid] != key){            if(key > array[mid])                min = mid + 1;            else if( key < array[mid])                max = mid - 1;            if(min > max)                return -1;             mid = (min + max) >> 1;        }        return mid;    }}