Submission #826768

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Source Code Expand

#include<bits/stdc++.h>

using namespace std;

int mod, ans, N, K, dp[2009][2009], s[2009][2009];
int fac[4000009], inv[4000009];

int pow (int a, int b, int mod)
{
    int p = 1;
    for (int i=0; (1<<i) <= b; i++)
    {
        if (b & (1 << i)) p = (1LL * p * a) % mod;
        a = (1LL * a * a) % mod;
    }
    return p;
}

int comb (int n, int k)
{
    if (k > n || k < 0) return 0;
    int ans = (1LL * fac[n] * inv[k]) % mod;
    ans = (1LL * ans * inv[n - k]) % mod;
    return ans;
}

void PreProc ()
{
    fac[0] = 1;
    for (int i=1; i<=N * K; i++)
        fac[i] = (1LL * fac[i - 1] * i) % mod;
    inv[N * K] = pow (fac[N * K], mod - 2, mod);
    for (int i=N * K - 1; i>=0; i--)
        inv[i] = (1LL * inv[i + 1] * (i + 1)) % mod;
}

int main ()
{
//freopen ("input", "r", stdin);
//freopen ("output", "w", stdout);

scanf ("%d %d", &N, &K), mod = 1e9 + 7;
if (K == 1)
{
    printf ("1\n");
    return 0;
}
PreProc ();
dp[0][0] = s[0][0] = 1;
for (int i=1; i<=N; i++)
    for (int j=1; j<=i; j++)
    {
        int coef = comb (i * K - j - 1, K - 2), sum = s[i - 1][i - 1];
        if (j > 1)
        {
            sum -= s[i - 1][j - 2];
            if (sum < 0) sum += mod;
        }
/*        for (int k=j - 1; k<i; k++)
            sum += dp[i - 1][k];
        dp[i][j] = sum * coef;*/
        dp[i][j] = (1LL * sum * coef) % mod;
        s[i][j] = s[i][j - 1] + dp[i][j];
        if (s[i][j] >= mod) s[i][j] -= mod;
    }
printf ("%d\n", (1LL * fac[N] * s[N][N]) % mod);
return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:66:47: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long long int’ [-Wformat=]
 printf ("%d\n", (1LL * fac[N] * s[N][N]) % mod);
                                               ^
./Main.cpp:42:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
 scanf ("%d %d", &N, &K), mod = 1e9 + 7;
                                       ^

Judge Result