Submission #565889

#	Time	Username	Problem	Language	Result	Execution time	Memory
565889		ngpin04	Duathlon (APIO18_duathlon)	C++14	0 / 100	141 ms	31072 KiB

count_triplets

#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define TASK ""
#define bit(x) (1LL << (x))
#define getbit(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end() 
using namespace std;
template <typename T1, typename T2> bool mini(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maxi(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}
mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());

int rand(int l, int r) {
	return l + rd() % (r - l + 1);
}
const int N = 2e5 + 5; 
const int oo = 1e9;
const long long ooo = 1e18;
const int mod = 1e9 + 7; // 998244353;
const long double pi = acos(-1);

vector <int> adj[N];
vector <int> g[N];
vector <int> s;

long long ans;

int num[N];
int low[N];
int sz[N];
int n,m,comp,node,timer;

void dfs(int u) {
	num[u] = low[u] = ++timer;
	node++;
	s.push_back(u);
	for (int v : adj[u]) {
		if (num[v])
			mini(low[u], num[v]);
		else {
			dfs(v);
			mini(low[u], low[v]);

			if (low[v] >= num[u]) {
				comp++;
				int w;
				do {
					w = s.back();
					s.pop_back();
					g[w].push_back(n + comp);
					g[n + comp].push_back(w);
				} while (w != v);

				g[n + comp].push_back(u);
				g[u].push_back(n + comp);
			}
		}
	}
}

void solve(int u, int p = -1) {
	long long tot = 0;
	sz[u] = (u <= n);
	for (int v : g[u]) if (v != p) {
		solve(v, u);
		sz[u] += sz[v];
		if (u > n) 
			tot += (long long) sz[v] * (sz[v] - 1);
	}
	if (u > n) {
		tot += (long long) (n - sz[u]) * ((n - sz[u]) - 1);
		ans -= tot * ((int) g[u].size() - 1);
	}

}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	#ifdef ONLINE_JUDGE
	// freopen(TASK".inp","r",stdin);
	// freopen(TASK".out","w",stdout);
	#endif
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u,v;
		cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}

	for (int i = 1; i <= n; i++) if (!num[i]) {
		s.clear();
		node = 0;
		dfs(i);
		ans += (long long) node * (node - 1) * (node - 2);
		solve(i);
	}

	cout << ans;
	return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 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