Submission #603070

#	Time	Username	Problem	Language	Result	Execution time	Memory
603070		benjaminkleyn	Duathlon (APIO18_duathlon)	C++17	8 / 100	105 ms	8200 KiB

count_triplets

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

int n, m;
vector<int> g[100000];
int par[100000];
ll sz[100000];
bool cyc[100000];

int find(int u)
{
    if (par[u] == u) return u;
    return par[u] = find(par[u]);
}

void unite(int u, int v)
{
    u = find(u), v = find(v);
    if (u == v) 
    {
        cyc[u] = true;
        return;
    }
    par[v] = u;
    sz[u] += sz[v];
}

int main()
{
    cin >> n >> m;
    for (int i = 0; i < n; i++)
        par[i] = i, sz[i] = 1;
    for (int i = 0, u, v; i < m; i++)
    {
        cin >> u >> v;
        unite(u - 1, v - 1);
        g[u - 1].push_back(v - 1);
        g[v - 1].push_back(u - 1);
    }

    ll res = 0;
    for (int i = 0; i < n; i++)
        if (par[i] == i)
        {
            if (cyc[i])
                res += sz[i] * (sz[i] - 1) * (sz[i] - 2);
            else
                for (ll j = 0; j < sz[i]; j++)
                    res += 2 * j * (sz[i] - 1 - j);
        }

    cout << res << '\n';

    return 0;
}

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