题解 | #二分查找-II#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 如果目标值存在返回下标，否则返回 -1
     * @param nums int整型一维数组 
     * @param target int整型 
     * @return int整型
     */
    public int search (int[] nums, int target) {
         // write code here
        if (nums.length == 0) {
            return -1;
        }
        if (nums.length ==1 && nums[0] != target) {
            return -1;
        }
        int left = 0;
        int right = nums.length - 1;
        int temp = -1;
        while (left <= right) {
            int middle = (right - left) / 2 + left;
            if (nums[middle] >= target) {
                right = middle - 1;
                temp = middle;
            } else if (nums[middle] < target) {
                left = middle + 1;
            } else {
                return middle;
            }
        }
        return temp;
    }
}