제출 #983542

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
983542		lev1106	철인 이종 경기 (APIO18_duathlon)	C++17	100 / 100	111 ms	38316 KiB

count_triplets

#include <bits/stdc++.h>
#define int long long
using namespace std;
int n, m, i, j, k, mask, x, y, ans, cnt, mxcnt, tim, sz[200001], col[200001], tin[200001], fup[200001], rt[200001], szz[200001];
bool u[200001], cyc, cyc2[200001];
vector<int> g[200001], g2[200001], vv;
vector<pair<int, int>> v;
set<pair<int, pair<int, int>>> st;

void dfss(int x, int pr, int r) {
	u[x] = 1;
	tin[x] = fup[x] = ++tim;
	for (auto y : g[x]) {
		if (y == pr) continue;
		if (!u[y]) {
			dfss(y, x, r);
			fup[x] = min(fup[x], fup[y]);
		}
		else {
			fup[x] = min(fup[x], tin[y]);
		}
	}
}

void dfs(int x, int pr, int cnt) {
	u[x] = 1;
	vv.push_back(x);
	for (auto y : g[x]) {
		if (y == pr) continue;
		if (!u[y]) {
			if (fup[y] >= tin[x]) {
				col[y] = mxcnt;
				dfs(y, x, mxcnt);
				g2[x].push_back(n + mxcnt);
				//cout << x << " " << n + mxcnt << "\n";
				while (g2[n + mxcnt].empty() || g2[n + mxcnt].back() != y) {
					//cout << vv.back() << " " << n + mxcnt << "\n";
					g2[vv.back()].push_back(n + mxcnt);
					g2[n + mxcnt].push_back(vv.back());
					vv.pop_back();
				}
				mxcnt++;
			}
			else {
				col[y] = cnt;
				dfs(y, x, cnt);
			}
		}
	}
}

void dfs2(int x, int pr, int r) {
	if (x <= n) sz[x] = 1;
	szz[x] = 1;
	u[x] = 1;
	rt[x] = r;
	for (auto y : g2[x]) {
		if (y == pr) continue;
		dfs2(y, x, r);
		sz[x] += sz[y];
		szz[x] += szz[y];
	}
}

void dfs3(int x, int pr) {
	u[x] = 1;
	for (auto y : g2[x]) if (!u[y]) dfs3(y, x);
	if (x > n) {
		//cout << x << " " << g2[x].size() << " " << rt[x] << " " << sz[rt[x]] << "\n";
		for (auto y : g2[x]) {
			if (y != pr && y <= n) {
				ans -= ((int)g2[x].size()) * (sz[y]) * (sz[y] - 1);
			}
		}
		ans -= ((int)g2[x].size()) * (sz[rt[x]] - sz[x]) * (sz[rt[x]] - sz[x] - 1);
	}
}

signed main() {
	cin.tie(0)->sync_with_stdio(0);
	#ifdef LOCAL
	freopen("input.txt", "r", stdin);
	#endif
	cin >> n >> m;
	while (m--) {
		cin >> x >> y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	for (i = 1; i <= 2 * n; i++) {
		if (!u[i]) {
			dfss(i, i, i);
		}
	}
	for (i = 1; i <= 2 * n; i++) u[i] = 0;
	for (i = 1; i <= 2 * n; i++) {
		if (!u[i]) {
			mxcnt++;
			dfs(i, i, mxcnt);
		}
	}
	for (i = 1; i <= 2 * n; i++) u[i] = 0;
	for (i = 1; i <= 2 * n; i++) {
		if (!u[i]) {
			dfs2(i, i, i);
		}
	}
	for (i = 1; i <= 2 * n; i++) u[i] = 0;
	//for (i = 1; i <= 2 * n; i++) cout << sz[i] << " ";
	for (i = 1; i <= n; i++) {
		if (!u[i]) {
			ans += (sz[rt[i]]) * (sz[rt[i]] - 1) * (sz[rt[i]] - 2);
			dfs3(i, i);
		}
	}
	cout << ans;
}

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