Submission #823109

#	Time	Username	Problem	Language	Result	Execution time	Memory
823109		Desh03	Paths (BOI18_paths)	C++17	23 / 100	3040 ms	3084 KiB

paths

#include <bits/stdc++.h>

using namespace std;

vector<vector<int>> g, cnt;
vector<int> c;
vector<bool> vis;

void dfs(int u, int mask, const bool &z) {
    vis[u] = 1;
    ++cnt[z][mask];
    for (int v : g[u]) {
        if (!vis[v] && !(mask >> c[v] & 1)) {
            dfs(v, mask | (1 << c[v]), z);
        }
    }
    vis[u] = 0;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, m, k;
    cin >> n >> m >> k;
    g.resize(n), cnt.resize(2, vector<int> (1 << k)), c.resize(n), vis.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> c[i];
        --c[i];
    }
    long long ans = 0;
    for (int i = 0; i < m; i++) {
        int u, v;
        cin >> u >> v;
        --u, --v;
        vis[v] = 1;
        dfs(u, 1 << c[u], 0);
        vis[u] = 1;
        dfs(v, 1 << c[v], 1);
        vis[u] = 0;
        for (int mask = 0; mask < (1 << k); mask++) {
            for (int mask2 = 0; mask2 < (1 << k); mask2++) {
                if ((mask & mask2) == 0) {
                    ans += cnt[0][mask] * cnt[1][mask2] << 1;
                }
            }
        }
        for (int j : {0, 1})
            for (int &x : cnt[j]) x = 0;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    cout << ans << '\n';
    return 0;
}

• Subtask 1: 23 / 23
• Subtask 2: 0 / 20
• Subtask 3: 0 / 27
• Subtask 4: 0 / 30