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Submission #784222

# Submission time Handle Problem Language Result Execution time Memory
784222 2023-07-15T21:33:03 Z NK_ Pipes (CEOI15_pipes) C++17
100 / 100
 796 ms 14536 KB 
// 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
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4180 KB Output is correct
2 Correct 2 ms 4180 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 4692 KB Output is correct
2 Correct 4 ms 4436 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 67 ms 4680 KB Output is correct
2 Correct 68 ms 4552 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 111 ms 5260 KB Output is correct
2 Correct 132 ms 4784 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 215 ms 6648 KB Output is correct
2 Correct 165 ms 6256 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 254 ms 11084 KB Output is correct
2 Correct 212 ms 7604 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 407 ms 12244 KB Output is correct
2 Correct 370 ms 9228 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 513 ms 14536 KB Output is correct
2 Correct 475 ms 9104 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 641 ms 14476 KB Output is correct
2 Correct 702 ms 9128 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 796 ms 13848 KB Output is correct
2 Correct 724 ms 10792 KB Output is correct