#include <iostream>
#include <algorithm>
#include <climits>
#include <cmath>
#include <map>
#include <set>
#include <bitset>
#include <iomanip>
#include <vector>
using namespace std;
inline int read() {
char c = getchar();
int x = 0, s = 1;
while (c < '0' || c > '9') {
if (c == '-')
s = -1;
c = getchar();
}
while (c >= '0' && c <= '9') {
x = x * 10 + c - '0';
c = getchar();
}
return x * s;
}
const int MAXN=1e5+1;
const int LG=17;
int** pa;
int *par,*h,*Up,*par1;
vector<int>* ma;
int get1(int& a)
{
return ((par1[a]==a)?a:par1[a]=get1(par1[a]));
}
void join1(int a,int b)
{
a=get1(a);
b=get1(b);
if(a!=b)
par1[a]=b;
}
int get(int& a)
{
return ((par[a]==a)?a:par[a]=get(par[a]));
}
bool join(int a,int b)
{
a=get(a);
b=get(b);
if(a!=b)
{
par[a]=b;
return 1;
}
return 0;
}
void dfs(int& x,int& p)
{
// cout<<x<<' '<<p<<endl;
pa[x][0]=p;
for(int j=1;j<LG;j++)
pa[x][j]=pa[pa[x][j-1]][j-1];
h[x]=h[p]+1;
for(auto y:ma[x])
if(y!=p)
dfs(y,x);
}
int lca(int x,int y)
{
if(h[x]>h[y])
swap(x,y);
for(int j=LG-1;j>=0;j--)
if(h[x]<=h[pa[y][j]])
y=pa[y][j];
if(x==y)
return x;
for(int j=LG-1;j>=0;j--)
if(pa[x][j]!=pa[y][j])
{
x=pa[x][j];
y=pa[y][j];
}
return pa[x][0];
}
void solve(int& x,int& p)
{
for(auto y:ma[x])
{
if(y!=p)
{
solve(y,x);
}
}
for(auto y:ma[x])
{
if(y!=p)
{
if(h[Up[x]]>h[Up[y]])
{
Up[x]=Up[y];
}
if(Up[y]==y)
{
cout<<x<<' '<<y<<endl;
}
}
}
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int n,m;
n=read();
m=read();
ma=new vector<int>[n+1];
par=new int[n+1];
par1=new int[n+1];
h=new int[n+1];
Up=new int[n+1];
pa=new int*[n+1];
for(int i=1;i<=n;i++)
{
pa[i]=new int[LG];
par[i]=par1[i]=Up[i]=i;
}
for(int i=0;i<m;i++)
{
int x,y;
x=read();
y=read();
// cin>>x>>y;
if(join(x,y))
{
// cout<<"Tree Edge "<<x<<' '<<y<<endl;
ma[x].push_back(y);
ma[y].push_back(x);
}
else
{
// cout<<"Cycle Edge "<<x<<' '<<y<<endl;
join1(x,y);
}
}
// cout<<"Tree Input:\n";
for(int i=1;i<=n;i++)
if(pa[i][0]==0)
dfs(i,i);
// cout<<"Cycle Input:"<<endl;
for(int y=1;y<=n;y++)
{
int x=get1(y);
// cout<<y<<' '<<x<<endl;
int c=lca(x,y);
if(h[Up[x]]>h[c])
{
Up[x]=c;
}
if(h[Up[y]]>h[c])
{
Up[y]=c;
}
}
// cout<<"Bridge Edges:\n";
for(int i=1;i<=n;i++)
if(pa[i][0]==i)
solve(i,i);
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
344 KB |
Output is correct |
2 |
Correct |
1 ms |
348 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
1116 KB |
Output is correct |
2 |
Correct |
3 ms |
1112 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
26 ms |
5968 KB |
Output is correct |
2 |
Correct |
27 ms |
5908 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
43 ms |
10208 KB |
Output is correct |
2 |
Correct |
50 ms |
11384 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
107 ms |
17232 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
143 ms |
28104 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
240 ms |
39356 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
302 ms |
50116 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
368 ms |
65440 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
420 ms |
65536 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |