#include "bits/stdc++.h"
using namespace std;
#define pb push_back
#define debug(args...) fprintf(stderr,args)
#define FOR(i,a,b) for(int i = a; i <= b; ++i)
#define REP(i,a,b) for(int i = a; i >= b; --i)
typedef long long ll;
typedef pair<int,int>pii;
const int maxn = 1e5 + 10;
int n, m;
struct dsu{
vector<int>par,sz;
void init(){
par.resize(n+1);
sz.resize(n+1);
FOR(i,1,n)
par[i] = i;
}
int root(int v){
return par[v] = (par[v] == v ? v : root(par[v]));
}
void merge(int x, int y){
x = root(x);
y = root(y);
if(x == y) return;
par[y] = x;
}
void end(){
par.clear();
sz.clear();
}
} T[2];
vector<pii>adj[maxn];
int cnt, cur;
vector<int>h, low;
vector<bool>mrk;
void dfs(int v, int par){
mrk[v] = true;
low[v] = h[v] = ++cur;
for(int i = 0; i < adj[v].size(); ++i){
int u = adj[v][i].first;
int e = adj[v][i].second;
if(e == par) continue;
if(!mrk[u]){
dfs(u,e);
low[v] = min(low[v],low[u]);
if(low[u] > h[v]) printf("%d %d\n",u,v);
}
else low[v] = min(low[v],h[u]);
}
}
void tarjan(){
h.resize(n+1);
low.resize(n+1);
mrk.resize(n+1);
FOR(i,1,n)
if(!mrk[i])
dfs(i,-1);
}
int main(){
scanf("%d%d",&n,&m);
T[0].init();
T[1].init();
FOR(i,1,m){
int a, b;
scanf("%d%d",&a,&b);
if(T[0].root(a) != T[0].root(b)){
++cnt;
adj[a].pb(pii(b,cnt));
adj[b].pb(pii(a,cnt));
T[0].merge(a,b);
}
else if(T[1].root(a) != T[1].root(b)){
++cnt;
adj[a].pb(pii(b,cnt));
adj[b].pb(pii(a,cnt));
T[1].merge(a,b);
}
}
T[0].end();
T[1].end();
tarjan();
return 0;
}
Compilation message
pipes.cpp: In function 'void dfs(int, int)':
pipes.cpp:53:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i < adj[v].size(); ++i){
~~^~~~~~~~~~~~~~~
pipes.cpp: In function 'int main()':
pipes.cpp:76:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&n,&m);
~~~~~^~~~~~~~~~~~~~
pipes.cpp:83:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&a,&b);
~~~~~^~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2688 KB |
Output is correct |
2 |
Correct |
4 ms |
2688 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
3200 KB |
Output is correct |
2 |
Correct |
8 ms |
3072 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
115 ms |
3132 KB |
Output is correct |
2 |
Correct |
115 ms |
2988 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
201 ms |
3952 KB |
Output is correct |
2 |
Correct |
233 ms |
3576 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
344 ms |
5804 KB |
Output is correct |
2 |
Correct |
309 ms |
5348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
514 ms |
11860 KB |
Output is correct |
2 |
Correct |
475 ms |
8952 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
809 ms |
13316 KB |
Output is correct |
2 |
Correct |
722 ms |
9976 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1042 ms |
15772 KB |
Output is correct |
2 |
Correct |
993 ms |
11640 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1303 ms |
15888 KB |
Output is correct |
2 |
Correct |
1216 ms |
11696 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1604 ms |
15116 KB |
Output is correct |
2 |
Correct |
1529 ms |
11788 KB |
Output is correct |