Submission #563666

#	Time	Username	Problem	Language	Result	Execution time	Memory
563666		colossal_pepe	Paths (BOI18_paths)	C++17	20 / 100	409 ms	315660 KiB

paths

#include <iostream>
#include <vector>
using namespace std;

using ll = long long;

int n, m, k, c[300005];
ll dp[300005][5][5][5];
vector<vector<int>> g;

ll solve() {
    ll ans = 0;
    if (k < 2) return ans;
    for (int u = 0; u < n; u++) {
        for (int v : g[u]) {
            dp[u][c[v]][0][0]++;
        }
        for (int x = 1; x <= k; x++) {
            if (x == c[u]) continue;
            ans += dp[u][x][0][0];
        }
    }
    if (k < 3) return ans;
    for (int u = 0; u < n; u++) {
        for (int v : g[u]) {
            for (int x = 1; x <= k; x++) {
                dp[u][c[v]][x][0] += dp[v][x][0][0];
            }
        }
        for (int x = 1; x <= k; x++) {
            if (x == c[u]) continue;
            for (int y = 1; y <= k; y++) {
                if (y == c[u] or y == x) continue;
                ans += dp[u][x][y][0];
            }
        }
    }
    return ans;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> m >> k;
    g.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> c[i];
    }
    while (m--) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    cout << solve() << endl;
    return 0;
}

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