Submission #784222

#	Time	Username	Problem	Language	Result	Execution time	Memory
784222		NK_	Pipes (CEOI15_pipes)	C++17	100 / 100	796 ms	14536 KiB

pipes

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'
#define pb push_back

template<class T> using V = vector<T>;

const int nax = 1e5+5;

struct DSU {
	int e[nax]; void init() { memset(e, -1, sizeof e); };
	int get(int x) { return e[x] < 0 ? x : e[x] = get(e[x]); }
	bool unite(int x, int y) {
		x = get(x), y = get(y); if (x == y) return 0;
		if (e[x] > e[y]) swap(x, y);
		e[x] += e[y]; e[y] = x; return 1;
	}
};

V<int> adj[nax];
int low[nax], disc[nax], t = 0;
bitset<nax> vis;

V<array<int, 2>> ans;

void dfs(int u, int p = -1) {
	vis[u] = 1;
	disc[u] = low[u] = t++;
	bool twi = 0;
	for(auto &v : adj[u]) if (v != p || twi) {
		if (vis[v]) low[u] = min(low[u], disc[v]);
		else {
			dfs(v, u);
			low[u] = min(low[u], low[v]);
			// cout << u << " " << low[u] << " " << disc[v] << endl;
			if (low[v] > disc[u]) {
				cout << u + 1 << " " << v + 1 << endl;
			}
		}
	} else twi = 1;
}


int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	memset(low, -1, sizeof low);
	memset(disc, -1, sizeof disc);
	vis.reset();

	int N, M; cin >> N >> M;
	DSU F, S; F.init(), S.init();

	int u, v;
	for(int e = 0; e < M; e++) {
		cin >> u >> v; --u, --v;
		if (F.unite(u, v) || S.unite(u, v)) {
			// cout << u << " " << v << endl;
			adj[u].pb(v);
			adj[v].pb(u);
		}
	}

	for(int i = 0; i < N; i++) if (!vis[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