The 9th Zhejiang Provincial Collegiate Programming Contest->Problem D:D - Draw Something Cheat

#include <bits/stdc++.h>
using namespace std;
int main() {
int t;
cin>>t;
while(t--) {
int num[107],num1[107];
char s[107];
int n;
cin>>n;
memset(num,0x3f3f3f3f,sizeof(num));
memset(num1,0,sizeof(num1));
for(int i=0; i<n; i++) {
scanf("%s",s);
memset(num1,0,sizeof(num1));
for(int j=0; j<12; j++)
num1[s[j]-'A']++;//记录字母出现的次数
for(int k=0; k<26; k++)
num[k]=min(num[k],num1[k]);//每次去记录的字符串中每个字母出现的最少的次数
}
for(int k=0; k<26; k++)
for(int j=0; j<num[k]; j++)
printf("%c",k+'A');
printf("\n");
}
return 0;
}