样例过但luogu上Compile Error

#include<cstdio>
#include<cstring>
char zm[5];
int f[101],answer;
int main()
{
    for(int i=0;i<4;i++)
    {
        gets(zm);
        for(int j=0;j<strlen(zm);j++) if(zm[j]>='A'&&zm[j]<='Z') f[zm[j]-'A']++;
    }
    for(int i='A';i<='Z';i++) if(f[i-'A']>answer) answer=f[i-'A'];
    for(int i=answer;i>=1;i--)
    {
        for(int j='A';j<='Z';j++)
        {
            if(f[j-'A']>=i) printf("*");
            else printf(" ");
            printf(" ");
        }
        printf("\n");
    }
    for(int i=65;i<=90;i++) printf("%c ",i);
    return 0;
}