Submission #527309

#	Time	Username	Problem	Language	Result	Execution time	Memory
527309		siewjh	Pipes (CEOI15_pipes)	C++17	100 / 100	1053 ms	15640 KiB

pipes

#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;
const int MAXN = 100'005;
vector<vector<int>> adjlist;
vector<int> tvis, lo;
int cnt = 0;
void dfs(int x, int par) {
	tvis[x] = lo[x] = cnt++;
	bool vpar = 0;
	for (auto nxt : adjlist[x]) {
		if (nxt == par && !vpar) {
			vpar = 1;
			continue;
		}
		if (tvis[nxt] != -1) lo[x] = min(lo[x], tvis[nxt]);
		else {
			dfs(nxt, x);
			lo[x] = min(lo[x], lo[nxt]);
			if (lo[nxt] > tvis[x]) cout << nxt << ' ' << x << '\n';
		}
	}
}
int root(int a, vector<int>& par) {
	if (par[a] == -1) return a;
	else return par[a] = root(par[a], par);
}
void merge(int a, int b, vector<int>& par, vector<int> &rank) {
	if (rank[a] > rank[b]) swap(a, b); // b has higher rank
	par[a] = b;
	if (rank[a] == rank[b]) rank[b]++;
}
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	int nodes, edges; cin >> nodes >> edges;
	vector<int> par1(nodes + 1, -1), par2(nodes + 1, -1), rank1(nodes + 1, -1), rank2(nodes + 1, -1);
	adjlist.resize(nodes + 1);
	tvis.resize(nodes + 1); lo.resize(nodes + 1);
	for (int i = 0; i < edges; i++) {
		int a, b; cin >> a >> b;
		if (root(a, par1) != root(b, par1)) {
			merge(root(a, par1), root(b, par1), par1, rank1);
			adjlist[a].push_back(b);
			adjlist[b].push_back(a);
		}
		else if (root(a, par2) != root(b, par2)) {
			merge(root(a, par2), root(b, par2), par2, rank2);
			adjlist[a].push_back(b);
			adjlist[b].push_back(a);
		}
	}
	for (int i = 1; i <= nodes; i++) tvis[i] = -1;
	for (int i = 1; i <= nodes; i++)
		if (tvis[i] == -1)
			dfs(i, -1);
	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