#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define oo 2000000000
const int N = 100010;
int n, m , cnt = 0 , dsu[N] , dsu2[N] , comp[N] , u , v , a ,b , depth[N];
bitset < N > bridge;
vector< pair<int,int> > g[N];
pair<int,int> parent[N];
inline int find(int u){ return (u == dsu[u] ? u : dsu[u] = find(dsu[u]));}
inline int find2(int u){ return (u == dsu2[u] ? u : dsu2[u] = find2(dsu2[u]));}
inline void DFS(int node,int prnt,int e,int d){
parent[node] = make_pair(prnt,e);
depth[node] = d;
if(bridge[e]) dsu2[node] = node; else dsu2[node] = find2(prnt);
for(int i=0;i<g[node].size();i++){
if(g[node][i].first != prnt) DFS(g[node][i].first,node,g[node][i].second,d+1);
}
}
inline int get(int node1,int node2){
if(node1 == node2) return find2(node1);
if(depth[node1] > depth[node2]){
bridge[parent[node1].second] = false;
return dsu2[node1] = dsu2[node2] = get(find2(parent[node1].first),node2);
}
bridge[parent[node2].second] = false;
return dsu2[node1] = dsu2[node2] = get(node1,find2(parent[node2].first));
}
int main() {
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++) dsu[i] = dsu2[i] = i , comp[i] = 1;
for(int i=0;i<m;i++){
scanf("%d%d",&u,&v);
a = find(u);
b = find(v);
if(a == b){
get(u,v);
}
else{
g[u].push_back(make_pair(v,cnt));
g[v].push_back(make_pair(u,cnt));
bridge[cnt] = true;
if(comp[a] > comp[b]){
DFS(v,u,cnt,depth[u] + 1);
comp[a] += comp[b];
comp[b] = 0;
dsu[b] = a;
}
else{
DFS(u,v,cnt,depth[v] + 1);
comp[b] += comp[a];
comp[a] = 0;
dsu[a] = b;
}
cnt++;
}
}
for(int i=1;i<=n;i++){
for(int j=0;j<g[i].size();j++){
if(i > g[i][j].first || !bridge[g[i][j].second]) continue;
printf("%d %d\n",i,g[i][j].first);
}
}
return 0;
}
Compilation message
pipes.cpp: In function 'void DFS(int, int, int, int)':
pipes.cpp:18:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<g[node].size();i++){
~^~~~~~~~~~~~~~~
pipes.cpp: In function 'int main()':
pipes.cpp:63:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j=0;j<g[i].size();j++){
~^~~~~~~~~~~~
pipes.cpp:34:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&n,&m);
~~~~~^~~~~~~~~~~~~~
pipes.cpp:37:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&u,&v);
~~~~~^~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
2688 KB |
Output is correct |
2 |
Correct |
3 ms |
2688 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
2944 KB |
Output is correct |
2 |
Correct |
7 ms |
2944 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
122 ms |
2884 KB |
Output is correct |
2 |
Correct |
125 ms |
2952 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
229 ms |
3200 KB |
Output is correct |
2 |
Correct |
271 ms |
3304 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
378 ms |
4096 KB |
Output is correct |
2 |
Correct |
331 ms |
4344 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
564 ms |
6888 KB |
Output is correct |
2 |
Correct |
491 ms |
6904 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
886 ms |
7516 KB |
Output is correct |
2 |
Correct |
828 ms |
7280 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1179 ms |
8644 KB |
Output is correct |
2 |
Correct |
1226 ms |
8680 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1446 ms |
8636 KB |
Output is correct |
2 |
Correct |
1456 ms |
8684 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1922 ms |
8412 KB |
Output is correct |
2 |
Correct |
1663 ms |
8532 KB |
Output is correct |