A

B

C

做法二

#include <lastweapon/number>
using namespace lastweapon;
const int N = int(1e2) + 9;
Int f[2][N][N][N];
int n, m;

int main() {

#ifndef ONLINE_JUDGE
     freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);
#endif

    RD(n, m, MOD);

    int p = 0, q = 1; f[p][0][1][1] = 1;

#define u f[q][kk][ii][jj]

    REP_1(a, n-1) {
        swap(p, q); RST(f[p]);
        REP(kk, min(a, m+1)) REP_1(ii, a) REP_1(jj, a) if (u) {
            REP_1(i, a+1) REP_1(j, a+1) {
                int k = kk + ((i > ii) && (j > jj) || (i <= ii) && (j <= jj));
                f[p][k][i][j] += u;
            }
        }
    }

    Int z = 0; REP_1(i, n) REP_1(j, n) z += f[p][m][i][j];
    cout << z << endl;
}