Submission #113031

#	Time	Username	Problem	Language	Result	Execution time	Memory
113031		MAMBA	Pipes (CEOI15_pipes)	C++11	70 / 100	5056 ms	14828 KiB

pipes

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h> 

using namespace std;

#define rep(i , j , k) for (int i = j; i < (int)k; i++)
#define pb push_back
#define mt make_tuple
#define all(x) x.begin(),x.end()

typedef long long ll;
typedef pair<int , int> pii;
typedef pair<ll, ll> pll;
typedef long double ld;
typedef complex<ld> point;
typedef pair<ld , ld> pld;
typedef vector<int> vi;

inline void fileIO(string s) {
//	freopen((s + ".in").c_str(), "r", stdin);
	freopen((s + ".out").c_str(), "w", stdout);
}

template<class T , class S>
inline bool smin(T &a, S b) { return (T)b < a ? a = b , 1 : 0; }
template<class T , class S>
inline bool smax(T &a, S b) { return a < (T)b ? a = b , 1 : 0; }

constexpr int N = 1e5 + 10;

constexpr int MOD = 1e6 + 7;

template<typename T>
inline T mod(T &v) { return v = (v % MOD + MOD) % MOD; }
template<typename S, typename T>
inline S add(S &l, T r) { return mod(l += r); }

int n, m;
vi adj[N];

int p[N];

int get_par(int v) {
	if (p[v]) 
		return p[v] = get_par(p[v]);
	return v;
}

inline bool merge(int v, int u) {
	v = get_par(v);
	u = get_par(u);

	if (v == u) return false;
	p[v] = u;
	return true;
}

bitset<N> mark;

int lvl[N], par[18][N], Tm , st[N], en[N];
void dfs(int v, int pa = 0) {
  	st[v] = Tm++;
	lvl[v] = lvl[pa] + 1;
	mark[v] = true;
	par[0][v] = pa;
	rep(i , 1 , 18)
		par[i][v] = par[i - 1][par[i - 1][v]];
	for (auto e : adj[v])
		if (e ^ pa)
			dfs(e , v);
	en[v] = Tm;
}

inline int LCA(int v, int u) {
	if (lvl[v]  < lvl[u]) swap(v, u);
	for (int i = 17; ~i; i--) 
      if (st[par[i][v]] > st[u] ||  en[par[i][v]] < en[u])
        v = par[i][v];
	return par[0][v];
}

int val[N];
void dfs2(int v , int pa = 0) {
	mark[v] = true;
	for (auto e : adj[v])
		if (e ^ pa) {
			dfs2(e , v);
			val[v] += val[e];
		}
	if (val[v] == 1)
		cout << v << ' ' << pa << '\n'; 
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

#ifndef LOCAL
	//fileIO("superposition");
#endif


	
	cin >> n >> m;

	rep(i , 0 , m) 
	{
		int u , v;
		cin >> u >> v;
		if (merge(u , v)) {
			adj[u].pb(v);
			adj[v].pb(u);
		}
	}

  	st[0] = -1;
  
	rep(i , 1 , n + 1)
		if (!mark[i])
			dfs(i);
	en[0] = Tm;
	cin.seekg(0);

	cin >> n >> m;
	rep(i , 0 , m) {
		int u , v;
		cin >> u >> v;
		int lca = LCA(u , v);
		if (lca == u || lca == v) {
			val[u ^ v ^ lca]++;
			val[lca]--;
		}
		else {
			val[u]++;
			val[v]++;
			val[lca] -= 2;
		}
	}

	mark.reset();

	rep(i , 1 , n + 1)
		if (!mark[i])
			dfs2(i);
			
	return 0;

}

Compilation message (stderr)

pipes.cpp: In function 'int LCA(int, int)':
pipes.cpp:78:7: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
       if (st[par[i][v]] > st[u] ||  en[par[i][v]] < en[u])
       ^~
pipes.cpp:80:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  return par[0][v];
  ^~~~~~

• 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: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10