제출 #559769

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
559769		GioChkhaidze	철인 이종 경기 (APIO18_duathlon)	C++14	100 / 100	133 ms	40100 KiB

count_triplets

#include <bits/stdc++.h>

#define ll long long
#define pb push_back

using namespace std;

const int N = 2e5 + 5;

bool us[N];
ll nds, ans;
int n, m, cmp, timer;
int disc[N], low[N], sz[N + N + N];
vector < int > rec, v[N], gr[N + N + N];

void dfs(int x, int p) {
	++nds;
	rec.pb(x);
	us[x] = true;
	disc[x] = low[x] = ++timer;
	for (int i = 0; i < v[x].size(); ++i) {
		int to = v[x][i];
		if (to == p) continue;
		if (!us[to]) {
			dfs(to, x);
			low[x] = min(low[x], low[to]);
			if (low[to] >= disc[x]) {
				++cmp;
				gr[x].pb(cmp + n);
				while (true) {
					int nd = rec.back();
					rec.pop_back();
					gr[cmp + n].pb(nd);
					if (nd == to) break;
				}
			}
		}
			else {
			low[x] = min(low[x], disc[to]);		
		}
	}
}

void slv(int x, int p) {
	sz[x] = (x <= n);
	ll grs = gr[x].size();
	for (int i = 0; i < grs; ++i) {
		int to = gr[x][i];
		slv(to, x);
		sz[x] += sz[to];
		if (x > n) ans -= grs * sz[to] * (sz[to] - 1);
	}
	if (x > n) ans -= grs * (nds - sz[x]) * (nds - sz[x] - 1);
}

main () {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL), cout.tie(NULL);
	cin >> n >> m;
	for (int i = 1; i <= m; ++i) {
		int a, b;
		cin >> a >> b;
		v[a].pb(b);
		v[b].pb(a);
	}
	for (int i = 1; i <= n; ++i) {
		if (!us[i]) {
			nds = 0;
			dfs(i, -1);
			ans += nds * (nds - 1) * (nds - 2);
			slv(i, -1);
		}
	}
	cout << ans << "\n";
}

컴파일 시 표준 에러 (stderr) 메시지

count_triplets.cpp: In function 'void dfs(int, int)':
count_triplets.cpp:21:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for (int i = 0; i < v[x].size(); ++i) {
      |                  ~~^~~~~~~~~~~~~
count_triplets.cpp: At global scope:
count_triplets.cpp:56:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   56 | main () {
      | ^~~~

• 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