#include <vector>
#include <algorithm>
#include <stdio.h>
#include <locale>
using namespace std;
#define FOR(i, j, k) for(int i=(j); i<=(k); i++)
#define FFOR(i, j, k) for(int i=(j); i<(k); i++)
#define DFOR(i, j, k) for(int i=(j); i>=(k); i--)
#define bug(x) cerr<<#x<<" = "<<(x)<<'\n'
#define pb push_back
#define mp make_pair
#define bit(s, i) (((s)>>(i))&1LL)
#define mask(i) ((1LL<<(i)))
#define builtin_popcount __builtin_popcountll
#define __builtin_popcount __builtin_popcountll
using ll=long long; using ld=long double;
//mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); const ld pi=acos(0)*2;
template <typename T> inline void read(T &x){char c; bool nega=0; while((!isdigit(c=getchar()))&&(c!='-')); if(c=='-'){nega=1; c=getchar();} x=c-48; while(isdigit(c=getchar())) x=x*10+c-48; if(nega) x=-x;}
template <typename T> inline void writep(T x){if(x>9) writep(x/10); putchar(x%10+48);}
template <typename T> inline void write(T x){if(x<0){ putchar('-'); x=-x;} writep(x);}
template <typename T> inline void writeln(T x){write(x); putchar('\n');}
#define taskname "Pipes"
class dsu{
public:
int n;
vector <int> r;
vector <pair <int, int>> edges;
void reset(int n){
this->n=n;
r.resize(n+1);
FOR(i, 1, n) r[i]=-1;
edges.clear();
}
int root(int u){
if(r[u]<0) return u;
return r[u]=root(r[u]);
}
bool unite(int u, int v){
int ou=u;
int ov=v;
u=root(u);
v=root(v);
if(u==v) return 0;
edges.pb(mp(ou, ov));
if(r[u]>r[v]) swap(u, v);
r[u]+=r[v];
r[v]=u;
return 1;
}
} d[2];
int n, m;
vector <int> g[100001];
vector <bool> done;
int cnt=0;
vector <int> low;
vector <int> num;
vector <int> p;
void dfs(int u){
done[u]=1;
cnt++;
num[u]=low[u]=cnt;
for(auto &x: g[u]) if(x==p[u]){
swap(x, g[u].back());
g[u].pop_back();
break;
}
for(int &v: g[u]) if(!done[v]){
p[v]=u;
dfs(v);
low[u]=min(low[u], low[v]);
}
else low[u]=min(low[u], num[v]);
for(int &v: g[u]) if(p[v]==u){
if(low[v]>num[u]){
write(u);
putchar(' ');
writeln(v);
}
p[v]=0;
}
}
int main(){
#ifdef Aria
if(fopen(taskname".in", "r"))
freopen(taskname".in", "r", stdin);
#endif // Aria
read(n);
read(m);
d[0].reset(n);
d[1].reset(n);
{
int u, v;
FOR(i, 1, m){
read(u);
read(v);
if(!d[0].unite(u, v)) d[1].unite(u, v);
}
}
FOR(b, 0, 1){
while(!d[b].edges.empty()){
auto p=d[b].edges.back();
d[b].edges.pop_back();
g[p.first].pb(p.second);
g[p.second].pb(p.first);
}
d[b].r.clear();
}
done.resize(n+1, 0);
num.resize(n+1, 0);
low.resize(n+1, 0);
p.resize(n+1, 0);
FOR(i, 1, n) if(!done[i]) dfs(i);
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2688 KB |
Output is correct |
2 |
Correct |
5 ms |
2688 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
3200 KB |
Output is correct |
2 |
Correct |
6 ms |
3072 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
53 ms |
3064 KB |
Output is correct |
2 |
Correct |
52 ms |
2976 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
88 ms |
3864 KB |
Output is correct |
2 |
Correct |
99 ms |
3456 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
161 ms |
5764 KB |
Output is correct |
2 |
Correct |
142 ms |
5464 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
246 ms |
11712 KB |
Output is correct |
2 |
Correct |
221 ms |
8608 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
377 ms |
13188 KB |
Output is correct |
2 |
Correct |
349 ms |
10188 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
527 ms |
15492 KB |
Output is correct |
2 |
Correct |
494 ms |
11156 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
606 ms |
15528 KB |
Output is correct |
2 |
Correct |
611 ms |
11196 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
672 ms |
14828 KB |
Output is correct |
2 |
Correct |
721 ms |
12140 KB |
Output is correct |