浙工大15新生赛 爱的密码

#include <iostream>
#include <algorithm>
using namespace std;
struct Hui {
char s, e;
}Lu[60];
int vis[60], vis2[60];
int main() {
int n;
while (scanf("%d", &n) != EOF) {
memset(Lu, 0, sizeof(Lu));
memset(vis, 0, sizeof(vis));
memset(vis2, 0, sizeof(vis2));
for (int i = 0; i < n; i++) {
cin >> Lu[i].s >> Lu[i].e;
}
for (int i = 0; i < n; i++) {
for(int j = 0; j < n; j++)
if (Lu[i].s == Lu[j].e) {
vis2[Lu[j].e - 'A']++;
}
vis[Lu[i].s - 'A']++;
}
int flag = 1;
for (int i = 0; i < 59; i++) {
if (Lu[i].s && vis[Lu[i].s - 'A'] != 1) { flag = 0; break; }
if (Lu[i].e && vis2[Lu[i].e - 'A'] != 1) { flag = 0; break; }
}
if (flag)
printf("Yes\n");
else
printf("No\n");
}
return 0;
}