Submission #457713

#	Time	Username	Problem	Language	Result	Execution time	Memory
457713		vanic	Pipes (CEOI15_pipes)	C++14	0 / 100	5074 ms	22792 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;

set < 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()){
			ms[y].insert(*ms[x].begin());
			ms[x].erase(ms[x].begin());
		}
	}
	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;
vector < pair < int, int > > edge;
bool bio[maxn];

bool dfs(int x, int prosl){
	bool p=0;
//	cout << x << endl;
	if(bio[x]){
		int ind1, ind2;
		for(int i=0; i<(int)put.size(); i++){
			if(put[i]==x){
				p=1;
				ind1=i;
				ind2=put.size()-1;
//				cout << "rez " <<  ms[put[i]].size() << ' ';
				ms[put[i]].erase(edge[ind1]);
				ms[put[i]].erase({edge[ind2].second, edge[ind2].first});
//				cout << ms[put[i]].size() << '\n';
			}
			else if(p){
				ind1=i;
				ind2=i-1;
//				cout << "rez " <<  ms[put[i]].size() << ' ';
				ms[put[i]].erase(edge[ind1]);
				ms[put[i]].erase({edge[ind2].second, edge[ind2].first});
//				cout << ms[put[i]].size() << '\n';
//				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(auto i=ms[x].begin(); i!=ms[x].end(); i++){
		if(!p && U1.find(i->second)==prosl){
			p=1;
		}
		else{
			edge.push_back(*i);
			if(dfs(U1.find(i->second), x)){
				bio[x]=0;
				put.pop_back();
				edge.pop_back();
				return 1;
			}
			edge.pop_back();
		}
	}
	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)].insert({a, b});
			ms[U1.find(b)].insert({b, a});
			U2.update(a, b);
		}
		else if(!U1.query(a, b)){
			ms[U1.find(a)].insert({a, b});
			ms[U1.find(b)].insert({b, a});
			assert(dfs(U1.find(a), -1));
		}
//		cout << "na " << i << endl;
	}
	for(int i=1; i<=n; i++){
		for(auto j=ms[i].begin(); j!=ms[i].end(); j++){
			if(j->first<j->second){
				printf("%d %d\n", j->first, j->second);
			}
		}
	}
	return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:135:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  135 |  scanf("%d%d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:138:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  138 |   scanf("%d%d", &a, &b);
      |   ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 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