hdu 5237 Base64

#include <stdio.h>
#include <string.h>
char map[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char s[10005];
char encoded[10005];
void base64()
{
long long t, slen, p, i, flag;
p = 0;
slen = strlen(s);
flag = slen % 3;
for(i = 0;i < slen;i += 3)
{
t = (s[i]<<16) + (s[i + 1]<<8) + s[i + 2];
encoded[p++] = map[(t&((1<<6) - 1)<<18)>>18];
//t>>6;
encoded[p++] = map[(t&((1<<6) - 1)<<12)>>12];
//t>>6;
encoded[p++] = map[(t&((1<<6) - 1)<<6)>>6];
//t>>6;
encoded[p++] = map[t&((1<<6) - 1)];
}
if(flag == 1)
{
encoded[p - 1] = '=';
encoded[p - 2] = '=';
}
else if(flag == 2)
encoded[p - 1] = '=';
encoded[p] = '\0';
//printf("%d\n", p);
}
int main()
{
int t, k, m, i;
scanf("%d", &t);
m = 1;
while(t--)
{
scanf("%d %s", &k, s);
while(k--)
{
base64();
strcpy(s, encoded);
}
printf("Case #%d: ", m++);
for(i = 0;i < strlen(encoded);i++)
printf("%c", encoded[i]);
printf("\n");
}
return 0;
}