杭电2074

#include<stdio.h>
#include<string.h>
char a[85][85];
int main()
{
    int n,k=0,i,j;
    char b,c,t;
    while(~scanf("%d %c %c",&n,&b,&c))
    {
        if(k++)
            printf("
");
        if(n==1)
            printf("%c
",b);
        else
        {
            if(n%4==1)//判断外框字母
            {
                t=b;
                b=c;
                c=t;
            }
            for(i=0; i<n/2+1; ++i)
            {
                for(j=i; j<n-i; ++j)
                    a[i][j]=a[n-1-i][j]=a[j][i]=a[j][n-1-i]=i%2?b:c;

            }
            a[0][n-1]=a[0][0]=a[n-1][0]=a[n-1][n-1]=' ';
            for(i=0; i<n; ++i)
            {
                for(j=0; j<n; ++j)
                    printf("%c",a[i][j]);
                printf("
");
            }
        }
    }
}