[HIHO]DIvide Product

Divided Product

题解

#include <iostream>

using namespace std;
//  f[0][0][1] = 1;
// for (i = 0; i < N; i++)
//     for (j = 0; j < N; j++)
//         for (k = 1; k <= M; k++)
//             if (f[i][j][k] > 0)
//                 for (l = j + 1; l <= N - i; l++)
//                     f[i + l][l][gcd[l * k]] = (f[i + l][l][gcd[l * k]] + f[i][j][k]) % 1000000007;
// k = 0;
// for (i = 1; i <= N; i++)
//     k = (k + f[N][i]     [M]) % 1000000007;
int N, M;
int cnt;
int gcd(int a,int b)
{
     return b==0?a:gcd(b,a%b);
}
int main()
{
    cin >> N >> M;
    cnt = 0;
    int f[N+1][N+1][M+1];
    for (int i =0;i<=N;++i)
        for (int j =0;j<=N;++j)
            for(int k =0;k<=M;++k)
                f[i][j][k] = 0;
    f[0][0][1] = 1;
    for(int i =0;i<=N;++i)
        for(int j=0;j<=N;++j)
            for(int k =0;k<=M;++k)
                if(f[i][j][k]>0)
                    for(int l=j+1;l<=N-i;++l)
                        f[i+l][l][gcd(l*k,M)] = (f[i][j][k] + f[i+l][l][gcd(l*k,M)]) % 1000000007;

    int k = 0;
    for(int i=0;i<=N;++i){
        k = (k + f[N][i][M]) % 1000000007;
        //    cout << f[N][i][M] <<endl;
    }
       cout << k << endl;
    return 0;
}