1124 Raffle for Weibo Followers

John got a full mark on PAT. He was so happy that he decided to hold a raffle（抽獎） 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<string>
#include <map>

using namespace std;
int m,n,s;
map<string,bool>mp;
string list[1005];
int main(){
    std::ios::sync_with_stdio(false);
    cin>>m>>n>>s;
    for(int i=1;i<=m;i++)cin>>list[i];
    for(int i=s;i<=m;i+=n){
        while (mp[list[i]]) i++;
        cout<<list[i]<<endl;
        mp[list[i]]=true;
    }
    if(mp.size()==0)cout<<"Keep going..."<<endl;
    return 0;
}