1124 Raffle for Weibo Followers （20 分）

John got a full mark on PAT. He was so happy that he decided to hold a raffle（抽奖） for his followers on Weibo -- that is, he would select winners from every N followers who forwarded his post, and give away gifts. Now you are supposed to help him generate the list of winners.

Input Specification:

Each input file contains one test case. For each case, the first line gives three positive integers M (≤ 1000), N and S, being the total number of forwards, the skip number of winners, and the index of the first winner (the indices start from 1). Then M lines follow, each gives the nickname (a nonempty string of no more than 20 characters, with no white space or return) of a follower who has forwarded John's post.

Note: it is possible that someone would forward more than once, but no one can win more than once. Hence if the current candidate of a winner has won before, we must skip him/her and consider the next one.

Output Specification:

For each case, print the list of winners in the same order as in the input, each nickname occupies a line. If there is no winner yet, print Keep going... instead.

Sample Input 1:

9 3 2
Imgonnawin!
PickMe
PickMeMeMeee
LookHere
Imgonnawin!
TryAgainAgain
TryAgainAgain
Imgonnawin!
TryAgainAgain

Sample Output 1:

PickMe
Imgonnawin!
TryAgainAgain

Sample Input 2:

2 3 5
Imgonnawin!
PickMe

Sample Output 2:

Keep going...

#include<iostream>
#include<map>
using namespace std;

int main(){
    int m,n,s;
    cin >> m >> n >> s;
    string str;
    map<string,int> mapp;
    bool flag = false;
    for(int i = 1; i <= m; i++){
        cin >> str;
        if(mapp[str] == 1) s++;
        if(mapp[str] == 0 && i == s){
            cout << str << endl;
            mapp[str] = 1;
            flag = true;
            s += n;
        }
    }
    if(!flag) cout << "Keep going...";
    return 0;
    
}