给定一个按照升序排列的整数数组 nums，和一个目标值 target。找出给定目标值在数组中的开始位置和结束位置。

你的算法时间复杂度必须是 O(log n) 级别。

如果数组中不存在目标值，返回 [-1, -1]。

示例 1:

输入: nums = [5,7,7,8,8,10],target = 8
输出: [3,4]

示例 2:

输入: nums = [5,7,7,8,8,10], target = 6
输出: [-1,-1]

public class Solution {
    public int[] searchRange(int[] nums, int target) {
        int[] result = new int[2];  
        result[0] = getBoundRange(nums, 0, nums.length-1, target, true);  
        result[1] = getBoundRange(nums, 0, nums.length-1, target, false);  
        return result;  
    }
    
    public int getBoundRange(int[]nums, int l, int r, int target, boolean left){  
        if(l>r){
            return -1;  
        }else{  
            int m = (l+r)/2;  
            if(nums[m]==target){  
                if(left){  
                    if(m==0 || nums[m-1]<target) return m;  
                    else return getBoundRange(nums, l, m-1, target, left);  
                }else {  
                    if(m==nums.length-1 || target<nums[m+1]) return m;  
                    else return getBoundRange(nums, m+1, r, target, left);  
                }  
            }else if (nums[m]>target) {  
                return getBoundRange(nums, l, m-1, target, left);  
            }else {  
                return getBoundRange(nums, m+1, r, target, left);  
            }  
        }  
    }
}