#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define OK puts("OK");
#define NO puts("NO");
#define YES puts("YES");
#define fr first
#define sc second
#define ret return
#define scanl(a) scanf("%lld",&a);
#define scanll(a,b) scanf("%lld %lld",&a, &b);
#define scanlll(a,b,c) scanf("%lld %lld %lld",&a,&b,&c);
#define scan1(a) scanf("%d",&a);
#define scan2(a,b) scanf("%d %d",&a, &b);
#define scan3(a,b,c) scanf("%d %d %d",&a,&b,&c);
#define all(s) s.begin(),s.end()
#define allr(s) s.rbegin(),s.rend()
#define pb push_back
#define sz(v) (int)v.size()
#define endi puts("");
#define eps 1e-12
const int N = 2e6+12,INF=1e9+7;
vector <pii> gg[N];
vector <int> g[N],cycle,v;
pii ver[N];
bool bosh[N],vis[N];
void dfs_cycle(int x,int p){
vis[x] = 1;
int i,j;
v.pb(x);
for (i=0;i<g[x].size();++i){
int to = g[x][i];
if (vis[to] == 1 && to != p){
bool f=0;
for (j=0;j<v.size();++j){
if (v[j] == to)f=1;
if (f){
cycle.pb(v[j]);
}
}
}
if (vis[to] == 0){
dfs_cycle(to,x);
}
}
v.pop_back();
}
int dlina[N],colichestvo[N];
pii ans;
void dfs_diametr(int x,int p){
int i;
vector <pii> tmp;
for (i=0;i<g[x].size();++i){
if (g[x][i] == p || bosh[g[x][i]])continue;
dfs_diametr(g[x][i],x);
tmp.pb({dlina[g[x][i]],colichestvo[g[x][i]]});
}
if (tmp.size() == 0){
colichestvo[x] = 1;
ret;
}
sort(allr(tmp));
int mx = tmp[0].fr,cnt = tmp[0].sc;
for (i=1;i<tmp.size();++i){
if (tmp[i].fr == mx){
cnt += tmp[i].sc;
}
}
dlina[x] = mx+1;
colichestvo[x] = cnt;
}
void calc(int x,int y,int m){
int dist = min(abs(x-y),m-abs(x-y));
dist += dlina[cycle[x]];
dist += dlina[cycle[y]];
if (ans.fr < dist){
ans.fr = dist;
ans.sc=0;
}
if (dist == ans.fr){
if (abs(x-y) == (m-abs(x-y))){
ans.fr += max(colichestvo[cycle[x]],1ll)*max(1ll,colichestvo[cycle[y]])*2ll;
}
else
ans.fr += colichestvo[cycle[x]]*colichestvo[cycle[y]]*1ll;
}
}
void posledniy_dfs(int x,int p){
vector <pii> tmp;
int i;
for (i=0;i<g[x].size();++i){
if (g[x][i] == p || bosh[g[x][i]])continue;
posledniy_dfs(g[x][i],x);
tmp.pb({dlina[g[x][i]],colichestvo[g[x][i]]});
}
if (tmp.size() <2)ret;
sort(allr(tmp));
if (tmp.empty())ret;
vector <int> xixi;
int mx = tmp[0].fr+1,cnt=tmp[0].sc,f=0;
if (mx == tmp[1].fr+1){
xixi.pb(cnt);
int sum=0,bla=0;
for (i=1;i<tmp.size();++i){
if (tmp[i].fr+1+mx > ans.fr){
ans.fr = tmp[i].fr+1+mx;
f=2;
}
if (ans.fr == tmp[i].fr+1+mx){
xixi.pb(tmp[i].sc);
f = max(f,1ll);
}
else break;
}
for (i=0;i<xixi.size();++i){
sum+=xixi[i];
bla += xixi[i]*xixi[i];
}
sum *= sum;
sum-=bla;
sum/=2;
if (f==2)ans.sc=sum;
else if (f==1){
ans.sc+=sum;
}
}
else {
int sum=0,bla=0;
for (i=1;i<tmp.size();++i){
if (tmp[i].fr+1+mx > ans.fr){
ans.fr = tmp[i].fr+1+mx;
f=2;
}
if (ans.fr == tmp[i].fr+1+mx){
xixi.pb(tmp[i].sc);
sum += cnt*tmp[i].sc;
f = max(f,1ll);
}
else break;
}
if (f==2)ans.sc=sum;
else if (f==1){
ans.sc+=sum;
}
}
}
pii merg(pii x,pii y){
if(x.fr>y.fr)
return x;
if(y.fr>x.fr)
return y;
return {x.fr,x.sc+y.sc};
}
main(){
int n,i,j;
cin>>n;
for (i=1;i<=n;++i){
int x,y;
cin>>x>>y;
g[x].pb(y);
g[y].pb(x);
gg[x].pb({y,i});
gg[y].pb({x,i});
}
dfs_cycle(1,0);
int m = cycle.size();
if (m == n){
cout <<n;
ret 0;
}
for (i=0;i<m;++i)
bosh[cycle[i]] = 1;
for (i=0;i<m;++i){
dfs_diametr(cycle[i],0);
// cout <<cycle[i]<<"-"<<dlina[cycle[i]]<<" ";
// cout <<colichestvo[cycle[i]]<<"\n";
}
int sz = m;
vector <int>otvet;
for (i=0;i<m;++i)
otvet.pb(cycle[i]);
for (i=0;i<m-1;++i)
otvet.pb(cycle[i]);
for (i=0;i<otvet.size();++i){
int vershina = otvet[i];
}
vector<pii>gg;
for (i=0;i<m;++i)
gg.pb({dlina[cycle[i]],colichestvo[cycle[i]]});
map <int,int> mp;
int p=0;
for(int i=0;i<sz-1;i++){
while(p < sz and p+p <= sz+i+i)
mp[gg[p].fr+p]+=gg[p].sc,p++;
mp[gg[i].fr+i] -= gg[i].sc;
if(!mp[gg[i].fr+i])
mp.erase(gg[i].fr+i);
pii tmp=*mp.rbegin();
ans = merg(ans,{tmp.fr + gg[i].fr-i, gg[i].sc * tmp.sc});
}
p=sz-1;
mp.clear();
for(int i=sz-1;i>=0;i--){
while(p+p>=sz+i+i)
mp[gg[p].fr+sz-p]+=gg[p].sc,p--;
if(mp.size()){
pii tmp=*mp.rbegin();
ans=merg(ans,{tmp.fr+gg[i].fr+i,gg[i].sc*tmp.sc});
}
}
for (i=0;i<m;++i){
posledniy_dfs(cycle[i],0);
}
cout <<ans.sc;
}
/*
16
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
6 10
10 11
10 12
5 13
2 14
2 15
15 16
7 1
10
1 2
2 3
3 4
4 7
3 5
3 8
5 6
8 9
9 10
3 1
*/
Compilation message
shymbulak.cpp: In function 'void dfs_cycle(long long int, long long int)':
shymbulak.cpp:32:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
32 | for (i=0;i<g[x].size();++i){
| ~^~~~~~~~~~~~
shymbulak.cpp:36:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for (j=0;j<v.size();++j){
| ~^~~~~~~~~
shymbulak.cpp: In function 'void dfs_diametr(long long int, long long int)':
shymbulak.cpp:57:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
57 | for (i=0;i<g[x].size();++i){
| ~^~~~~~~~~~~~
shymbulak.cpp:68:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
68 | for (i=1;i<tmp.size();++i){
| ~^~~~~~~~~~~
shymbulak.cpp: In function 'void posledniy_dfs(long long int, long long int)':
shymbulak.cpp:98:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
98 | for (i=0;i<g[x].size();++i){
| ~^~~~~~~~~~~~
shymbulak.cpp:111:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
111 | for (i=1;i<tmp.size();++i){
| ~^~~~~~~~~~~
shymbulak.cpp:122:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
122 | for (i=0;i<xixi.size();++i){
| ~^~~~~~~~~~~~
shymbulak.cpp:137:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
137 | for (i=1;i<tmp.size();++i){
| ~^~~~~~~~~~~
shymbulak.cpp:135:19: warning: unused variable 'bla' [-Wunused-variable]
135 | int sum=0,bla=0;
| ^~~
shymbulak.cpp: At global scope:
shymbulak.cpp:165:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
165 | main(){
| ^
shymbulak.cpp: In function 'int main()':
shymbulak.cpp:199:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
199 | for (i=0;i<otvet.size();++i){
| ~^~~~~~~~~~~~~
shymbulak.cpp:200:13: warning: unused variable 'vershina' [-Wunused-variable]
200 | int vershina = otvet[i];
| ^~~~~~~~
shymbulak.cpp:167:13: warning: unused variable 'j' [-Wunused-variable]
167 | int n,i,j;
| ^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
65 ms |
94316 KB |
Output is correct |
| 2 |
Correct |
64 ms |
94316 KB |
Output is correct |
| 3 |
Correct |
64 ms |
94316 KB |
Output is correct |
| 4 |
Correct |
64 ms |
94316 KB |
Output is correct |
| 5 |
Correct |
64 ms |
94444 KB |
Output is correct |
| 6 |
Correct |
64 ms |
94316 KB |
Output is correct |
| 7 |
Correct |
64 ms |
94316 KB |
Output is correct |
| 8 |
Correct |
65 ms |
94316 KB |
Output is correct |
| 9 |
Correct |
64 ms |
94316 KB |
Output is correct |
| 10 |
Correct |
65 ms |
94316 KB |
Output is correct |
| 11 |
Correct |
65 ms |
94316 KB |
Output is correct |
| 12 |
Correct |
64 ms |
94328 KB |
Output is correct |
| 13 |
Correct |
65 ms |
94316 KB |
Output is correct |
| 14 |
Correct |
65 ms |
94344 KB |
Output is correct |
| 15 |
Correct |
66 ms |
94316 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
66 ms |
94572 KB |
Output is correct |
| 2 |
Correct |
66 ms |
94444 KB |
Output is correct |
| 3 |
Correct |
65 ms |
94444 KB |
Output is correct |
| 4 |
Correct |
67 ms |
94444 KB |
Output is correct |
| 5 |
Correct |
70 ms |
94828 KB |
Output is correct |
| 6 |
Correct |
77 ms |
95084 KB |
Output is correct |
| 7 |
Correct |
71 ms |
94956 KB |
Output is correct |
| 8 |
Correct |
70 ms |
94828 KB |
Output is correct |
| 9 |
Correct |
69 ms |
94828 KB |
Output is correct |
| 10 |
Correct |
69 ms |
94828 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
274 ms |
106348 KB |
Output is correct |
| 2 |
Correct |
271 ms |
106476 KB |
Output is correct |
| 3 |
Correct |
179 ms |
114284 KB |
Output is correct |
| 4 |
Correct |
189 ms |
106092 KB |
Output is correct |
| 5 |
Correct |
189 ms |
106092 KB |
Output is correct |
| 6 |
Correct |
507 ms |
117228 KB |
Output is correct |
| 7 |
Correct |
370 ms |
111340 KB |
Output is correct |
| 8 |
Correct |
314 ms |
117868 KB |
Output is correct |
| 9 |
Correct |
325 ms |
118124 KB |
Output is correct |
| 10 |
Correct |
290 ms |
119660 KB |
Output is correct |
| 11 |
Correct |
348 ms |
121900 KB |
Output is correct |
| 12 |
Correct |
360 ms |
123016 KB |
Output is correct |
