1124. Raffle for Weibo Followers (20)

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.

9 3 2Imgonnawin!PickMePickMeMeMeeeLookHereImgonnawin!TryAgainAgainTryAgainAgainImgonnawin!TryAgainAgainSample Output 1:
PickMeImgonnawin!TryAgainAgainSample Input 2:
2 3 5Imgonnawin!PickMeSample Output 2:
Keep going...
#include<iostream>#include<map>#include<vector>#include<string>using namespace std;int M, N, S;map<string, bool> msb;vector<string> vs;int main(){	scanf("%d%d%d", &M, &N, &S);	vs.push_back(" ");	string s;	for (int i = 0; i < M; i++)	{		cin >> s;		vs.push_back(s);		msb[s] = false;	}	int i = S;	if (vs.size() - 1 < S)	{		cout << "Keep going..." << endl; return 0;	}	while (i <= M)	{		if (msb[vs[i]] == false)		{			cout << vs[i] << endl;			msb[vs[i]] = true;			i += N;		}		else {			i++;		}	}	return 0;}