老超时……求大神……

#include <iostream>
#include <cstring> 
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <algorithm>
using namespace std;
int a[1000+5];
int main()
{
    int top,x,y;
    for (;;)
    {
        scanf("%d%d",&x,&y);
        top=0;
        while (x!=0)
        {
            top++;
            a[top]=x % y;
            x=x / y;
            if (a[top]<0) 
            {
                a[top]=a[top]-y;
                x++;
            }
            if (a[top]>=10) a[top]+=55; 
        }
        for (int i=top; i>=1; i--) 
        {
            if (a[i]<10) printf("%d",a[i]);
            else 
            {
                char p=(char)a[i];
                printf("%c",p);
            }
        }
        printf("(base%d)",y);
        printf("\n");
    }
    return 0;
}