Submission #230148

#	Time	Username	Problem	Language	Result	Execution time	Memory
230148		ruler	Pipes (CEOI15_pipes)	C++14	100 / 100	1434 ms	13944 KiB

pipes

// IOI 2021
#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#define ends ' '
#define die(x) return cout << x << endl, 0
#define all(v) v.begin(), v.end()
#define sz(x) (int)(x.size())
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) { cerr << ends << H; debug_out(T...); }
#define debug(...) cerr << "{" << #__VA_ARGS__ << "}:", debug_out(__VA_ARGS__)
typedef long long ll;
typedef pair<int, int> pii;
const int INF = 1e9;
const ll MOD = 1e6 + 7;
 
////////////////////////////////////////////////////////////////////

const int N = 1e5 + 2;

int H[N];
vector<int> G[N];
bool M[N];

struct DSU {
	int P[N];
	int GetPar(int v) { return P[v] ? P[v] = GetPar(P[v]) : v; }
	bool Merge(int v, int u) {
		v = GetPar(v), u = GetPar(u);
		if (v == u) return false;
		P[u] = v;
		return true;
	}
} T, B;

int DFS(int v, int p = 0) {
	M[v] = true;
	int dp = H[v];
	bool f = false;
	for (int u : G[v]) {
		if (u == p && !f) { f = true; continue; }
		if (!M[u]) H[u] = H[v] + 1, dp = min(dp, DFS(u, v));
		else dp = min(dp, H[u]);
	}
	if (p && dp == H[v]) cout << p << ends << v << endl;
	return dp;
}

int main() {

	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	mt19937 Rnd(time(0));

	int n, m; cin >> n >> m;
	for (int i = 0; i < m; i++) {
		int v, u; cin >> v >> u;
		if (T.Merge(v, u) || B.Merge(v, u)) G[v].push_back(u), G[u].push_back(v);
	}	
	for (int i = 1; i <= n; i++) if (!T.P[i]) DFS(i);

	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10