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 == null || nums.length == 0) return -1;

        int left = 0, right = nums.length - 1;
        while(left + 1 < right){
            int mid = left + (right - left)/2;
            if(nums[mid] >= target){
                right = mid;
            }else{
                left = mid;
            }
        }

        if(nums[left] == target){
            return left;
        }else if(nums[right] == target){
            return right;
        }else{
            return -1;
        }
    }
}