leetcode Search for a Range

代码：

#include<iostream>
#include<vector>

using namespace std;

int searchSmallest(int A[], int n, int target){
    int l = 0;
    int r = n - 1;
    while (l <= r){
        int mid = (l + r) / 2;
        if (target <= A[mid]){
            r = mid-1;
        }
        else{
            l = mid+1;
        }
    }
    if (A[r + 1] == target)
        return r + 1;
    else
        return -1;
}

int searchLargest(int A[], int n, int target){
    int l = 0;
    int r = n - 1;
    while (l <= r){
        int mid = (l+ r) / 2;
        if (target >= A[mid]){
            l = mid+1;
        }
        else{
            r = mid - 1;
        }
    }
    if (A[l-1] == target)
        return l - 1;
    else
        return -1;
}

vector<int> searchRange(int A[], int n, int target) {
    vector<int> result;
    int a = searchSmallest(A, n, target);
    int b = searchLargest(A, n, target);
    result.push_back(a);
    result.push_back(b);
    return result;
}

int main(){
    int a[] = {1};
    cout << searchSmallest(a, 1, 1) << endl;
    cout << searchLargest(a, 1, 1) << endl;
    vector<int> result = searchRange(a, 1, 1);
    for (int i = 0; i < result.size(); i++){
        cout << result[i] << endl;
    }
}