[UVa] 343 - What base is this?

I was too lazy when I saw this problem for the very first time 2 years ago. Solving problems that required parsing a string were too tedious for me back then. Well, guess what it generated a great code for future problems from this domain.

#include <stdio.h>
#include <math.h>
#include <string.h>
#define isChar(i) ((i>='A'&&i<='Z')||(i>='0'&&i<='9'))
typedef unsigned long long ULL;
int vals[1000];
char input[1000], val1[1000], val2[1000];
ULL getVal(char *a, int base, int ln)
{
    int len = ln, i;
    ULL val=0;
    for (i=len-1 ; i>=0 ; i--)
    {
        val = val + (vals[a[i]]) * (int)pow((double)base,(len-1-i));
    }
    return val;
}

int setVals()
{
    int i;
    for (i=0 ; i<=9 ; i++)
    {
        vals[i+'0'] = i;
    }
    for (i='A' ; i<='Z' ; i++)
    {
        vals[i] = (i-55);
    }
}

int parser(char *a, int *l1, int *l2, int *mb1, int *mb2)
{
    int i, j, min;
    for (i=0 ; !isChar(a[i]) ; i++);
    min=-1;
    for (j=0 ; isChar(a[i]) ; i++, j++)
    {
        val1[j]=a[i];
        if (vals[a[i]]>min)
            min = vals[a[i]];
    }
    val1[j]='\0';
    *l1=j;
    *mb1=min+1;

    for ( ; !isChar(a[i]) ; i++);
    min=-1;
    for (j=0 ; isChar(a[i]) ; i++, j++)
    {
        val2[j]=a[i];
        if (vals[a[i]]>min)
            min = vals[a[i]];
    }
    val2[j]='\0';
    *l2=j;
    *mb2=min+1;
}

int main()
{
    int l1, l2, minb1, minb2, f, i, j;
    setVals();

    while (gets(input))
    {
        parser(input,&l1,&l2,&minb1,&minb2);

        f=0;

        for (i=(minb1>1?minb1:2) ; i<=36 && !f ; i++)
        {
            for (j=(minb2>1?minb2:2) ; j<=36 && !f ; j++)
            {
                if (getVal(val1,i,l1) == getVal(val2,j,l2))
                {
                    printf("%s (base %d) = %s (base %d)\n",val1,i,val2,j);
                    f=1;
                }
            }
        }

        if (!f) printf("%s is not equal to %s in any base 2..36\n",val1,val2);

    }
    return 0;
}