USACO 2.4 Fractions to Decimals

mark：题意很简单。。。输出小数形式，要标记循环节。不难就是写起来挺麻烦，开辟一个数组来标记余数是否出现过可以找到循环节。而且要记录循环节起始出现的位置。写的比较恶心。还有76个字符一行，要注意换行。最长的是1/9991，循环周期是1632位。。。代码写的比较恶心。。。

代码：

# include <stdio.h>
# include <string.h>


int vis[1000010], ans[1000010] ;
char str[1000000] ;


int main ()
{
    int cnt, cc, n, d, i;
    freopen ("fracdec.in", "r", stdin) ;
    freopen ("fracdec.out", "w", stdout) ;
    
    while (~scanf ("%d%d", &n, &d))
    {
        memset (vis, 0, sizeof(vis)) ;
        cnt = 0 ;
        cnt = sprintf (str, "%d.", n/d) ;
        n = (n%d)*10 ;
        if (n == 0) cnt = cnt+sprintf (str+cnt, "0") ;
        for (cc = 1 ; n && !vis[n]; cc++, n=(n%d)*10)
            vis[n]=cc, ans[cc]=n/d ;
        if (n==0)
            for (i = 1 ; i < cc ; i++) cnt = cnt + sprintf (str+cnt, "%d", ans[i]) ;
        else
        {
            for (i = 1 ; i < vis[n] ; i++) cnt = cnt + sprintf (str+cnt, "%d", ans[i]) ;
            cnt = cnt + sprintf (str+cnt, "(") ;
            for (i = vis[n] ; i < cc ; i++) cnt = cnt + sprintf (str+cnt, "%d", ans[i]) ;
            cnt = cnt + sprintf (str+cnt, ")") ;
        }

        for (i = 0 ; str[i] ; i++){
            if (i != 0 && i % 76 == 0) printf ("
") ;
            printf ("%c", str[i]) ;
        }
        printf ("
") ;
        
    }
    return 0 ;
}