34. 在排序数组中查找元素的第一个和最后一个位置/C++

class Solution {
public:
    void binarySearch(vector<int>& nums, int target, int left, int right, int& l, int& r){
        if(left > right)
            return;
        
        int mid = (left+right)/2;
        if(nums[mid] == target){
            if(mid < l) l=mid;
            if(mid > r) r=mid;
            binarySearch(nums,target,mid+1,right,l,r);
            binarySearch(nums,target,left,mid-1,l,r);
        }else if(nums[mid] < target)
            binarySearch(nums,target,mid+1,right,l,r);
        else
            binarySearch(nums,target,left,mid-1,l,r);
    }
    vector<int> searchRange(vector<int>& nums, int target) {
        if(nums.empty()) return vector<int>{-1,-1};
        
        int l=nums.size(),r=0;
        binarySearch(nums,target,0,nums.size()-1,l,r);
        if(l==nums.size() && r==0)
            return vector<int>{-1,-1};
        else
            return vector<int>{l,r};
    }
};