Submission #457696

#	Time	Username	Problem	Language	Result	Execution time	Memory
457696		vanic	Pipes (CEOI15_pipes)	C++14	40 / 100	5095 ms	21188 KiB

pipes

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cassert>

using namespace std;

const int maxn=1e5+5;

vector < pair < int, int > > ms[maxn];

struct union_find{
	int parent[maxn];
	union_find(){
		for(int i=0; i<maxn; i++){
			parent[i]=i;
		}
	}
	int find(int x){
		if(parent[x]==x){
			return x;
		}
		return parent[x]=find(parent[x]);
	}
	void update(int x, int y){
		x=find(x);
		y=find(y);
		if(ms[x].size()>ms[y].size()){
			swap(x, y);
		}
		parent[x]=y;
		pair < int, int > p;
		while(!ms[x].empty()){
			p=ms[x].back();
			ms[x].pop_back();
			if(y==find(p.second)){
				continue;
			}
			ms[y].push_back(p);
		}
	}
	bool query(int x, int y){
		return find(x)==find(y);
	}
};

struct union_find2{
	int parent[maxn];
	int sz[maxn];
	union_find2(){
		for(int i=0; i<maxn; i++){
			parent[i]=i;
			sz[i]=1;
		}
	}
	int find(int x){
		if(x==parent[x]){
			return x;
		}
		return parent[x]=find(parent[x]);
	}
	void update(int x, int y){
		x=find(x);
		y=find(y);
		if(sz[x]>sz[y]){
			swap(x, y);
		}
		parent[x]=y;
		sz[y]+=sz[x];
	}
	bool query(int x, int y){
		return find(x)==find(y);
	}
};

union_find U1;
union_find2 U2;

vector < int > put;
bool bio[maxn];

bool dfs(int x, int prosl){
	bool p=0;
//	cout << x << endl;
	if(bio[x]){
		for(int i=0; i<(int)put.size(); i++){
			if(put[i]==x){
				p=1;
			}
			else if(p){
//				cout << "upd " << put[i] << ' ' << put[i-1] << endl;
				U1.update(put[i], put[i-1]);
			}
		}
		return 1;
	}
	bio[x]=1;
	put.push_back(x);
	for(int i=0; i<(int)ms[x].size(); i++){
		if(!p && U1.find(ms[x][i].second)==prosl){
			p=1;
		}
		else if(U1.find(ms[x][i].second)!=x){
			if(dfs(U1.find(ms[x][i].second), x)){
				bio[x]=0;
				put.pop_back();
				return 1;
			}
		}
	}
	put.pop_back();
	bio[x]=0;
	return 0;
}

int main(){
	int n, m;
	scanf("%d%d", &n, &m);
	int a, b;
	for(int i=0; i<m; i++){
		scanf("%d%d", &a, &b);
		if(!U2.query(a, b)){
			ms[U1.find(a)].push_back({a, b});
			ms[U1.find(b)].push_back({b, a});
			U2.update(a, b);
		}
		else if(!U1.query(a, b)){
			ms[U1.find(a)].push_back({a, b});
			ms[U1.find(b)].push_back({b, a});
			assert(dfs(U1.find(a), -1));
		}
//		cout << "na " << i << endl;
	}
	for(int i=1; i<=n; i++){
		for(int j=0; j<(int)ms[i].size(); j++){
			if(U1.find(ms[i][j].first)<U1.find(ms[i][j].second)){
				printf("%d %d\n", ms[i][j].first, ms[i][j].second);
			}
		}
	}
	return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:122:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |  scanf("%d%d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:125:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |   scanf("%d%d", &a, &b);
      |   ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 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