Submission #265419

#	Time	Username	Problem	Language	Result	Execution time	Memory
265419		DS007	Duathlon (APIO18_duathlon)	C++14	10 / 100	1121 ms	1048576 KiB

count_triplets

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

const int N = 1e5, M = 2e5;
vector<int> adj[N];
bool explored[N];
int n, m, dp[N][3], ans;

void dfs(int v, int p = -1) {
    //cerr << v << endl;
    explored[v] = true;
    int s1 = 0, s2 = 0;
    dp[v][0] = 1;

    for (int i : adj[v]) {
        if (i != p){
            dfs(i, v);
            dp[v][0] += dp[i][0];
            dp[v][1] += dp[i][0] + dp[i][1];
            dp[v][2] += dp[i][1] * 2;
            s2 += dp[i][1];
            s1 += dp[i][0];
        }
    }

    for (int i : adj[v]) {
        if (i != p) {
            s2 -= dp[i][1];
            s1 -= dp[i][0];
            dp[v][2] += s2 * dp[i][0] * 2;
            dp[v][2] += s1 * dp[i][0];
            s2 += dp[i][1];
            s1 += dp[i][0];
        }
    }

    ans += dp[v][2];
}

int solveTestCase() {
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for (int i = 0; i < n; i++) {
        if (!explored[i])
            dfs(i);
        cerr << dp[i][0] << " " << dp[i][1] << " " << dp[i][2] << endl;
    }

    cout << ans;
    return 0;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int t = 1;
    //cin >> t;
    while (t--)
        solveTestCase();
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 10 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10