#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
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);
| ~~~~~^~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
3788 KB |
Output is correct |
2 |
Correct |
3 ms |
3788 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
121 ms |
4160 KB |
Output is correct |
2 |
Correct |
60 ms |
4132 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
208 ms |
9412 KB |
Output is correct |
2 |
Correct |
142 ms |
9236 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
856 ms |
13928 KB |
Output is correct |
2 |
Correct |
361 ms |
15560 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
4485 ms |
21188 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
5095 ms |
6252 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
5069 ms |
7272 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
5069 ms |
6944 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
5070 ms |
6988 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
5086 ms |
7092 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |