oj.uz

Submission #441202

# Submission time Handle Problem Language Result Execution time Memory
441202 2021-07-04T15:48:01 Z sinamhdv Pipes (CEOI15_pipes) C++11
100 / 100
 1394 ms 15512 KB 
// CEOI15_pipes
// 2nd solution
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int mod = 1000 * 1000 * 1000 + 7;
const int INF = 1e9 + 100;
const ll LINF = 1e18 + 100;

#ifdef DEBUG
#define dbg(x) cout << #x << " = " << (x) << endl << flush;
#define dbgr(s, f) { cout << #s << ": "; for (auto _ = (s); _ != (f); _++) cout << *_ << ' '; cout << endl << flush; }
#else
#define dbg(x) ;
#define dbgr(s, f) ;
#endif
#define FOR(i, a, b) for (int i = (a); i < (int)(b); i++)
#define fast_io ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define mp make_pair
#define fr first
#define sc second
#define endl '\n'

#define MAXN 100010

int n, m;
vector<int> adj[MAXN];
bitset<MAXN> mark;
int val[MAXN], h[MAXN];
int ef[2 * MAXN], eto[2 * MAXN];

int tree[MAXN], be[MAXN];
int getroot(int x, int *dpar)
{
	return dpar[x] == x ? x : dpar[x] = getroot(dpar[x], dpar);
}
bool merge(int x, int y, int *dpar)
{
	x = getroot(x, dpar);
	y = getroot(y, dpar);
	if (x == y) return false;
	dpar[x] = y;
	return true;
}

void dfs1(int v, int epar = 0)
{
	mark[v] = true;
	for (int e : adj[v])
	{
		int u = ef[e] ^ eto[e] ^ v;
		if (mark[u])
		{
			if (h[u] < h[v] && e != epar) val[u]--, val[v]++;
			continue;
		}
		h[u] = h[v] + 1;
		dfs1(u, e);
	}
}

void dfs2(int v, int epar = 0)
{
	mark[v] = true;
	for (int e : adj[v])
	{
		int u = ef[e] ^ eto[e] ^ v;
		if (!mark[u]) dfs2(u, e), val[v] += val[u];
	}
	if (epar && val[v] == 0) cout << ef[epar] << ' ' << eto[epar] << endl;
}

int32_t main(void)
{
	fast_io;
	cin >> n >> m;

	iota(tree, tree + n + 5, 0);
	iota(be, be + n + 5, 0);

	int ecnt = 0;

	FOR(i, 0, m)
	{
		int x, y;
		cin >> x >> y;
		if (merge(x, y, tree) || merge(x, y, be))
		{
			ecnt++;
			ef[ecnt] = x;
			eto[ecnt] = y;
			adj[x].pb(ecnt);
			adj[y].pb(ecnt);
		}
	}

	FOR(i, 1, n + 1) if (!mark[i]) dfs1(i);

	mark.reset();
	FOR(i, 1, n + 1) if (!mark[i]) dfs2(i);

	return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 3148 KB Output is correct
2 Correct 6 ms 3028 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 121 ms 3024 KB Output is correct
2 Correct 117 ms 2892 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 204 ms 3916 KB Output is correct
2 Correct 234 ms 3404 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 341 ms 5816 KB Output is correct
2 Correct 287 ms 5260 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 468 ms 11652 KB Output is correct
2 Correct 420 ms 8132 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 769 ms 13044 KB Output is correct
2 Correct 673 ms 9968 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 950 ms 15460 KB Output is correct
2 Correct 926 ms 10640 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1177 ms 15512 KB Output is correct
2 Correct 1136 ms 10548 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1394 ms 14796 KB Output is correct
2 Correct 1337 ms 11648 KB Output is correct