Submission #666467

#	Time	Username	Problem	Language	Result	Execution time	Memory
666467		finn__	Amusement Park (CEOI19_amusementpark)	C++17	42 / 100	227 ms	460 KiB

amusementpark

#include <bits/stdc++.h>
using namespace std;

#define MOD 998244353

int main()
{
    size_t n, m;
    cin >> n >> m;

    vector<vector<bool>> g(n, vector<bool>(n, 0));
    for (size_t i = 0; i < m; i++)
    {
        unsigned u, v;
        cin >> u >> v;
        g[u - 1][v - 1] = 1;
    }

    vector<int64_t> dp(1 << n, 0);
    dp[0] = 1;

    for (unsigned i = 1; i < 1 << n; i++)
    {
        unsigned const p = __builtin_popcount(i);
        vector<unsigned> s;
        for (unsigned k = 0; k < n; k++)
            if (i & (1 << k))
                s.push_back(k);

        for (unsigned j = 0; j < 1 << p; j++)
        {
            bool is_independent = 1;

            for (unsigned k = 0; k < p && is_independent; k++)
                if (j & (1 << k))
                    for (unsigned h = 0; h < p && is_independent; h++)
                        if (j & (1 << h))
                            if (g[s[k]][s[h]] || g[s[h]][s[k]])
                                is_independent = 0;

            if (is_independent)
            {
                unsigned t = 0;
                for (unsigned k = 0; k < p; k++)
                    if (j & (1 << k))
                        t ^= (1 << s[k]);

                assert(__builtin_popcount(t) == __builtin_popcount(j));

                dp[i] = (dp[i] +
                         ((__builtin_popcount(t) & 1) ? 1 : -1) * dp[i ^ t]) %
                        MOD;
            }
        }
    }

    cout << (dp[(1 << n) - 1] * m * 499122177) % MOD << '\n';
}

Compilation message (stderr)

amusementpark.cpp: In function 'int main()':
amusementpark.cpp:22:28: warning: comparison of integer expressions of different signedness: 'unsigned int' and 'int' [-Wsign-compare]
   22 |     for (unsigned i = 1; i < 1 << n; i++)
      |                          ~~^~~~~~~~
amusementpark.cpp:30:32: warning: comparison of integer expressions of different signedness: 'unsigned int' and 'int' [-Wsign-compare]
   30 |         for (unsigned j = 0; j < 1 << p; j++)
      |                              ~~^~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 0 / 21
• Subtask 5: 0 / 37