#include<iostream>
#include<algorithm>
#include<iomanip>
#include<cmath>
#include<cstring>
#include<vector>
#include<queue>
#include<stack>
#include<tuple>
#include<set>
#include<map>
#include<random>
#include<chrono>
using namespace std;
const int MAX_N=5e5+5;
int maxd[MAX_N];
int cntd[MAX_N];
int maxd2[MAX_N];
int maxdup[MAX_N];
vector<int>g[MAX_N];
int n;
int cnt;
int ans;
int root;
void dfsdown(int u,int par)
{
for(int v:g[u])
{
if(v==par)continue;
dfsdown(v,u);
if(maxd[v]+1>maxd[u])
{
maxd2[u]=maxd[u];
maxd[u]=maxd[v]+1;
cntd[u]=cntd[v];
}
else if(maxd[v]+1==maxd[u])
{
maxd2[u]=maxd[u];
cntd[u]+=cntd[v];
}
}
if(g[u].size()==1)cntd[u]=1;
}
void dfsup(int u,int par)
{
for(int v:g[u])
{
if(v==par)continue;
int cur=maxd[u];
if(maxd[v]+1==maxd[u])cur=maxd2[u];
cur++;
maxdup[v]=max(maxdup[u],cur);
dfsup(v,u);
}
}
int eachtwo(vector<int>& v)
{
int sum=0;
int pairs=0;
for(int x:v)sum+=x;
for(int x:v)
{
sum-=x;
pairs+=(x*sum);
}
return pairs;
}
void dfs(int u,int par)
{
vector<pair<int,int>>V;//depth,cnt
vector<pair<int,int>>all;
vector<pair<int,int>>otherV;
int up=maxdup[u],curans=0,curcnt=0;
for(int v:g[u])
{
if(v==par)continue;
dfs(v,u);
all.push_back({maxd[v]+1,cntd[v]});
}
if(g[u].size()==1)return;
sort(all.begin(),all.end());
V.push_back(all[0]);
otherV.push_back({all[0].first,1});
for(int i=1;i<all.size();i++)
{
if(all[i].first==all[i-1].first)
{
V.back().second+=all[i].second;
otherV.back().second++;
}
else {V.push_back(all[i]);otherV.push_back({all[i].first,1});}
}
if(otherV.back().second>=3)
{
int b=V.back().first;
vector<int>only;
for(int v:g[u])
{
if(v==par)continue;
if(maxd[v]+1==b)only.push_back(cntd[v]);
}
int eachtwob=eachtwo(only);
curans=2*b*b;
curcnt=eachtwob;
}
else
{
if(otherV.back().second==2)
{
if(V.size()>=2)
{
int b=V.back().first,cb=V.back().second;
int a=V[V.size()-2].first,ca=V[V.size()-2].second;
curans=b*(a+b);
curcnt=ca*cb;
}
}
else
{
if(V.size()==2)
{
if(otherV[0].second>=2)
{
int b=V[1].first;
int a=V[0].first;
vector<int>only;
for(int v:g[u])
{
if(v==par)continue;
if(maxd[v]+1==a)only.push_back(cntd[v]);
}
int eachtwoa=eachtwo(only);
curans=2*a*b;
curcnt=eachtwoa;
}
}
else if(V.size()>2)
{
int b=V.back().first,cb=V.back().second;
int a=V[V.size()-2].first,ca=V[V.size()-2].second;
int c=V[V.size()-3].first,cc=V[V.size()-3].second;
curans=b*(a+c);
curcnt=cc*ca;
}
}
}
///without up
if(otherV.back().second>=2)
{
int b=V.back().first;
vector<int>only;
for(int v:g[u])
{
if(v==par)continue;
if(maxd[v]+1==b)only.push_back(cntd[v]);
}
int eachtwob=eachtwo(only);
if(2*b*up>curans)
{
curans=2*b*up;
curcnt=eachtwob;
}
else if(2*b*up==curans)
{
curcnt+=eachtwob;
}
}
else
{
if(V.size()>=2)
{
int b=V.back().first,cb=V.back().second;
int a=V[V.size()-2].first,ca=V[V.size()-2].second;
if((a+b)*up>curans)
{
curans=(a+b)*up;
curcnt=ca*cb;
}
else if((a+b)*up==curans)
{
curcnt+=ca*cb;
}
}
}
///with up
if(curans>ans)
{
ans=curans;
cnt=curcnt;
}
else if(curans==ans)
{
cnt+=curcnt;
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin>>n;
for(int i=1;i<n;i++)
{
int u,v;
cin>>u>>v;
g[u].push_back(v);
g[v].push_back(u);
}
if(n==2)
{
cout<<0<<" "<<1<<"\n";
return 0;
}
for(int i=1;i<=n;i++)
{
if(g[i].size()==1)continue;
root=i;
break;
}
dfsdown(root,0);
dfsup(root,0);
dfs(root,0);
cnt+=(ans==0);
cout<<ans<<" "<<cnt<<"\n";
return 0;
}
Compilation message
road.cpp: In function 'void dfs(int, int)':
road.cpp:97:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
97 | for(int i=1;i<all.size();i++)
| ~^~~~~~~~~~~
road.cpp:161:38: warning: unused variable 'cb' [-Wunused-variable]
161 | int b=V.back().first,cb=V.back().second;
| ^~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
16988 KB |
Output is correct |
| 2 |
Correct |
2 ms |
16988 KB |
Output is correct |
| 3 |
Incorrect |
3 ms |
16988 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
16988 KB |
Output is correct |
| 2 |
Correct |
2 ms |
16988 KB |
Output is correct |
| 3 |
Incorrect |
3 ms |
16988 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
16988 KB |
Output is correct |
| 2 |
Correct |
2 ms |
16988 KB |
Output is correct |
| 3 |
Incorrect |
3 ms |
16988 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
