A1124 Raffle for Weibo Followers （20 分）

#include<cstdio>
#include<set>
#include<string>
using namespace std;
set<string> sq;
int main()
{
	int m, n, s;
	char str[25];
	scanf("%d %d %d", &m, &n, &s);
	int i = 1,num=0;
	bool flag = 0;
	for(int i=1;i<=m;i++)
	{
		scanf("%s", str);
		if (i == s)
		{
			if (sq.find(str) == sq.end())
			{
				printf("%s\n", str);
				num++;
				//printf("%d\n", i);
				sq.insert(str);
			}
		}
		if (flag == 1)
		{
			if (sq.find(str) != sq.end()) continue;
			else
			{
				printf("%s\n", str);
				num++;
				//printf("%d\n", i);
				sq.insert(str);
				flag = 0;
				s = i;
				continue;
			}
		}
		if ((i - s) % n == 0&&(i-s)>0)
		{
			if (sq.find(str) == sq.end())
			{
				printf("%s\n", str);
				num++;
				//printf("%d\n", i);
				sq.insert(str);
			}
			else
			{
				flag = 1;
			}
		}
	}
	if (num == 0) printf("Keep going...\n");
	return 0;
}

https://blog.youkuaiyun.com/liuchuo/article/details/60467398
这里map默认初始值都是0，思路非常值得学习。

#include <iostream>
#include <map>
using namespace std;
int main() {
    int m, n, s;
    scanf("%d%d%d", &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 = s + 1;
        if (i == s && mapp[str] == 0) {
            mapp[str] = 1;
            cout << str << endl;
            flag = true;
            s = s + n;
        }
    }
    if (flag == false) cout << "Keep going...";
    return 0;
}