Light OJ 1068

数位DP

#include <cstdio>
#include <cstring>
using namespace std;

const int MAX_DIGIT = ;
const int MAX_K = ;

long long n;
int f[MAX_DIGIT];
long long memoize[MAX_DIGIT][MAX_DIGIT * ][MAX_DIGIT * ];
int k;

int to_digits(long long a)
{
    int ret = ;
    while (a > )
    {
        f[ret++] = a % ;
        a /= ;
    }
    return ret;
}

long long dfs(int digit, bool less, int sum, int remainder)
{
    if (digit < )
    {
        return sum ==  && remainder == ;
    }
    if (less && memoize[digit][sum][remainder] != -)
    {
        return memoize[digit][sum][remainder];
    }
    int limit = less ?  : f[digit];
    long long ret = ;
    for (int i = ; i <= limit; i++)
    {
        ret += dfs(digit - , less || i < f[digit], (sum + i) % k, (remainder *  + i) % k);
    }
    if (less)
    {
        memoize[digit][sum][remainder] = ret;
    }
    return ret;
}

long long work(long long n)
{
    if (n < )
    {
        return ;
    }
    if (n == )
    {
        return ;
    }
    int len = to_digits(n);
    if (k >= MAX_DIGIT * )
    {
        return ;
    }
    return dfs(len - , false, , );
}

int main()
{
    int t;
    scanf("%d", &t);
    for (int i = ; i <= t; i++)
    {
        int a, b;
        scanf("%d%d%d", &a, &b, &k);
        memset(memoize, -, sizeof(memoize));
        printf("Case %d: %lld\n", i, work(b) - work(a - ));
    }
    return ;
}