Submission #781220

#	Time	Username	Problem	Language	Result	Execution time	Memory
781220		NK_	Pipes (CEOI15_pipes)	C++17	0 / 100	490 ms	65536 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 f first
#define s second
#define mp make_pair
#define pb push_back

using pi = pair<int, int>;
template<class T> using V = vector<T>;

const int nax = 1e5+5;

pi stk[nax];
int disc[nax], crit[nax], cur, ti;
V<pi> adj[nax];

void dfs(int u, int x) {
	disc[u] = ++ti;

	for(auto e : adj[u]) {
		int v, i; tie(v, i) = e;
		if (i == x) continue;

		if (disc[v] == -1) {
			stk[cur++] = mp(u, i);
			dfs(v, i);
		} else {
			int up = disc[v];
			crit[i] = 0;
			// cout << v << " " << up << endl;
			while(cur > 0 && disc[stk[cur - 1].f] >= up) crit[stk[--cur].s] = 0;
		}		
	}
}


int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	cur = ti = 0;
	for(int i = 0; i < nax; i++) {
		stk[i] = mp(-1, -1);
		disc[i] = -1;
		crit[i] = 1;
		adj[i] = {};
	}	

	int N, M; cin >> N >> M;
	V<pi> E(M);
	for(int e = 0; e < M; e++) {
		int u, v; cin >> u >> v; --u, --v;
		E[e] = mp(u + 1, v + 1);
		adj[u].pb(mp(v, e));
		adj[v].pb(mp(u, e));
	}

	for(int i = 0; i < N; i++) if (disc[i] == -1) dfs(i, -1);

	for(int i = 0; i < M; i++) if (crit[i]) {
		cout << E[i].f << " " << E[i].s << endl;
	}

    return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10