Submission #668736

#	Time	Username	Problem	Language	Result	Execution time	Memory
668736		AmirAli_H1	Pipes (CEOI15_pipes)	C++17	20 / 100	5070 ms	5352 KiB

pipes

// In the name of Allah

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

typedef long long int	ll;
typedef long double	ld;
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pll;

#define all(x)		(x).begin(),(x).end()
#define len(x)		((ll) (x).size())
#define F		first
#define S		second
#define pb		push_back
#define sep             ' '
#define endl            '\n'
#define Mp		make_pair
#define debug(x)	cerr << #x << ": " <<  x << endl;
#define kill(x)		cout << x << '\n', exit(0);
#define set_dec(x)	cout << fixed << setprecision(x);
#define file_io(x,y)	freopen(x, "r", stdin); freopen(y, "w", stdout);

int n, m;
const int maxn = 1e5 + 5;
int p[maxn], sz[maxn];
int px[maxn], szx[maxn];
vector<pii> adj[maxn];
vector<pii> ans;
bitset<maxn> mark;
int h[maxn], mn[maxn];

void dfs(int v, int p = -1, int j = -1) {
	mark[v] = 1; mn[v] = h[v];
	for (auto f : adj[v]) {
		int u = f.F, i = f.S;
		if (!mark[u]) {
			h[u] = h[v] + 1;
			dfs(u, v, i);
			mn[v] = min(mn[v], mn[u]);
		}
		else if (i != j) {
			mn[v] = min(mn[v], h[u]);
		}
	}
	
	if (mn[v] >= h[v] && p != -1) {
		ans.pb(Mp(min(p, v), max(p, v)));
	}
}

int get(int a) {
	return ((p[a] == a) ? a : p[a] = get(p[a]));
}

void merge(int a, int b) {
	a = get(a); b = get(b);
	if (a == b) return ;
	if (sz[a] > sz[b]) swap(a, b);
	p[a] = b; sz[b] += sz[a]; sz[a] = 0;
}

int main() {
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	
	cin >> n >> m;
	
	iota(p, p + n, 0); fill(sz, sz + n, 1);
	iota(px, px + n, 0); fill(szx, szx + n, 1);
	
	for (int i = 0; i < m; i++) {
		int u, v;
		cin >> u >> v; u--; v--;
		bool flag = 0;
		if (!flag && get(u) != get(v)) {
			flag = 1;
			merge(u, v);
			adj[u].pb(Mp(v, i)); adj[v].pb(Mp(u, i));
		}
		swap(p, px); swap(sz, szx);
		if (!flag && get(u) != get(v)) {
			flag = 1;
			merge(u, v);
			adj[u].pb(Mp(v, i)); adj[v].pb(Mp(u, i));
		}
		swap(p, px); swap(sz, szx);
	}
	
	for (int i = 0; i < n; i++) {
		if (!mark[i]) dfs(i);
	}
	
	for (auto f : ans) {
		cout << f.F + 1 << sep << f.S + 1 << endl;
	}
		
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 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