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…
AC代码
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main() {
char Person[1001][21];
int cnt = 0, k = 0;
int M, N, S; //转发的总量 中奖间隔 第一位中奖者的序号
cin >> M >> N >> S;
for (int i = 1; i <= M; i++) scanf("%s", Person[i]); //得到转发人的昵称
int Lucky[1001] = { 0 };
if (S > M) { printf("Keep going...\n"); return 0; } //第一位中奖者超出总人数
printf("%s\n", Person[S]);
Lucky[k++] = S; //得到第一位中奖者 标记其已中过奖
if (N + S > M) return 0; //如果下位中奖者超出总人数
for (int i = S+1; i <= M; i++) {
cnt++;
if (cnt == N) {
int flag = 1;
for (int j = 0; j < k; j++) //如果此人已领过奖
if (strcmp(Person[i], Person[Lucky[j]]) == 0) { flag = 0; break; }
if (flag) {
Lucky[k++] = i; //标记其已中过奖
printf("%s\n", Person[i]);
cnt = 0; //重新计数
}
else cnt--; //已领过奖的人作废 不做计数
}
}
return 0;
}