JAVA 二分查找

        前提：使用二分查找，需要数组有序，不然会影响二分查找结果，可以先使用Arrarys.sort()方法对数组排序，再使用二分查找法：

public int search(int[] nums, int target) {

        Arrays.sort(nums);

        int low = 0 , high = nums.length-1;

        while (low <= high) {
            int mid = (high - low)/2 + low;
            int num = nums[mid];                //找到给定排序后数组的中间值
            if (num == target) return mid;
            if (num >target) high=mid-1;        //如果给定查找值比中间值小，则在数组左边查找
            else low = mid+1;
        }

        return -1;
    }