I didn't use any long arithmethic but i think it should passes the first test. But judge says WA !!! Help please if you can


#include <iostream>

using namespace std;

long long d[10001][2];

int main () {
    int n, k;

    cin >> n >> k;

    d[0][0] = 1;
    d[0][1] = 0;

    int i, j;

    for (i = 1; i <= n; ++i) {

        d[i][1] = 0;
        for (j = 1; j <= k; ++j) {
            if (n - j < 0)
                continue;

            d[i][1] += d[i - j][0];
        }

        d[i][0] = d[i - 1][0] + d[i - 1][1];
    }

    cout << d[n][0] + d[n][1];

    return 0;
}