//#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
typedef long long llo;
#define mp make_pair
#define pb push_back
#define a first
#define b second
#define endl '\n'
llo n;
vector<pair<llo,llo>> adj[1000001];
vector<pair<llo,llo>> adj2[1000001];
llo par[1000001];
llo find(llo no){
if(par[no]==no){
return no;
}
par[no]=find(par[no]);
return par[no];
}
llo dp[1000001][2];
pair<llo,llo> cur;
vector<pair<llo,llo>> pp;
vector<pair<llo,llo>> xx;
vector<llo> tt;
void dfs(llo no,llo par2=-1){
if(no==cur.b){
pp=xx;
}
tt.pb(no);
for(auto j:adj[no]){
/*if(j.a==cur.a and no==cur.b){
continue;
}
if(j.a==cur.b and no==cur.a){
continue;
}*/
if(j.a!=par2){
xx.pb({j.a,j.b});
dfs(j.a,no);
xx.pop_back();
}
}
}
llo vis[1000001];
llo maa=0;
void dfs2(llo no,llo par2=-1){
dp[no][0]=0;
dp[no][1]=0;
vector<llo> ss;
llo su=0;
for(auto j:adj2[no]){
if(j.a!=par2){
dfs2(j.a,no);
// dp[no][0]=max(dp[no][0],j.b+dp[j.a][0]);
su+=dp[j.a][1];
ss.pb(dp[j.a][0]+j.b);
}
}
sort(ss.begin(),ss.end());
reverse(ss.begin(),ss.end());
dp[no][1]=0;
dp[no][0]=0;
for(llo i=0;i<ss.size();i++){
if(i==2){
break;
}
if(i==0){
if(ss[i]>=0){
dp[no][0]+=ss[i];
}
}
if(ss[i]>=0){
dp[no][1]+=ss[i];
}
}
dp[no][1]=max(dp[no][1],dp[no][0]);
maa=max(maa,dp[no][1]);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin>>n;
for(llo i=0;i<n;i++){
par[i]=i;
}
vector<pair<pair<llo,llo>,llo>> ed;
for(llo i=0;i<n;i++){
llo aa,cc;
cin>>aa>>cc;
aa--;
llo x=find(i);
llo y=find(aa);
if(x!=y){
par[x]=y;
adj[i].pb({aa,cc});
adj[aa].pb({i,cc});
}
else{
ed.pb({{i,aa},cc});
//cout<<i<<":"<<aa<<":"<<cc<<endl;
}
}
llo ans=0;
for(auto j:ed){
cur=j.a;
llo cost=0;
tt.clear();
dfs(j.a.a);
pp.pb({cur.a,j.b});
for(auto i:pp){
vis[i.a]=1;
}
vector<pair<pair<llo,llo>,llo>> pc;
pc.pb(j);
for(auto i:tt){
for(auto k:adj[i]){
if(vis[k.a]+vis[i]<2){
//adj2[i].pb(k);
}
else{
if(k.a<i){
pc.pb({{i,k.a},k.b});
}
}
}
}
/* for(auto i:pc){
cout<<i.a.a<<","<<i.a.b<<","<<i.b<<endl;
}*/
if(pp.size()==2){
llo zz5=0;
for(auto i:tt){
for(auto k:adj[i]){
//cout<<i<<":"<<k.a<<":"<<k.b<<endl;
if(vis[k.a]+vis[i]<2){
adj2[i].pb(k);
}
else{
//if(k.a<i){
zz5=max(zz5,k.b);
//}
}
}
}
maa=0;
for(auto i:pp){
dfs2(i.a);
}
zz5=max(zz5,j.b);
cost=max(cost,maa);
cost=max(cost,dp[pp[0].a][1]+dp[pp[1].a][1]);
cost=max(cost,dp[pp[0].a][0]+dp[pp[1].a][0]+zz5);
ans+=cost;
//cout<<cost<<":"<<endl;
continue;
}
for(auto ii:pc){
for(auto i:tt){
adj2[i].clear();
}
for(auto i:tt){
for(auto k:adj[i]){
if(vis[k.a]+vis[i]<2){
adj2[i].pb(k);
}
else{
if(k.a==ii.a.a and i==ii.a.b){
continue;
}
if(k.a==ii.a.b and i==ii.a.a ){
continue;
}
//adj2[i].pb(k);
// pc.pb({{i,k.a},k.b});
}
}
}
maa=0;
for(auto i:pc){
if(i.a.a!=ii.a.a or i.a.b!=ii.a.b){
adj2[i.a.a].pb({i.a.b,i.b});
adj2[i.a.b].pb({i.a.a,i.b});
}
}
dfs2(tt[0]);
cost=max(cost,dp[tt[0]][1]);
cost=max(cost,maa);
//cout<<ii.a.a<<"<"<<ii.a.b<<","<<ii.b<<endl;
//cout<<dp[tt[0]][1]<<endl;
}
ans+=cost;
continue;
/*for(auto i:tt){
cout<<i<<",";
}
cout<<endl;*/
llo kk=0;
vector<llo> re;
for(auto i:pp){
dfs2(i.a);
kk+=dp[i.a][1];
llo ac=0;
for(auto j:adj2[i.a]){
ac+=dp[j.a][1];
}
re.pb(ac);
//cout<<i.a<<":"<<1<<endl;
}
/* for(auto j:pp){
cout<<j.a<<":"<<j.b<<endl;
cout<<dp[j.a][0]<<"."<<dp[j.a][1]<<endl;
}*/
cost=max(cost,kk);
llo xx=pp.size();
for(llo i=0;i<pp.size();i++){
llo ind=i;
llo su=0;
for(llo cot=0;cot<xx-1;cot++){
ind++;
if(ind==xx){
ind=0;
}
//cout<<i<<".."<<ind<<endl;
su+=pp[ind].b;
llo cur2=su;
cur2+=dp[pp[i].a][0]-dp[pp[i].a][1];
cur2+=dp[pp[ind].a][0]-dp[pp[ind].a][1];
cost=max(cost,cur2+kk);
su-=(dp[pp[ind].a][1]);
su+=re[ind];
}
}
for(auto i:pp){
vis[i.a]=0;
}
ans+=cost;
}
cout<<ans<<endl;
return 0;
}
Compilation message
islands.cpp: In function 'void dfs2(llo, llo)':
islands.cpp:72:15: warning: comparison of integer expressions of different signedness: 'llo' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
72 | for(llo i=0;i<ss.size();i++){
| ~^~~~~~~~~~
islands.cpp: In function 'int main()':
islands.cpp:242:16: warning: comparison of integer expressions of different signedness: 'llo' {aka 'long long int'} and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
242 | for(llo i=0;i<pp.size();i++){
| ~^~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
32 ms |
47340 KB |
Output is correct |
| 2 |
Correct |
36 ms |
47340 KB |
Output is correct |
| 3 |
Correct |
45 ms |
47468 KB |
Output is correct |
| 4 |
Correct |
31 ms |
47340 KB |
Output is correct |
| 5 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 6 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 7 |
Correct |
32 ms |
47340 KB |
Output is correct |
| 8 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 9 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 10 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 11 |
Correct |
34 ms |
47340 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
88 ms |
47596 KB |
Output is correct |
| 2 |
Correct |
32 ms |
47468 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
32 ms |
47724 KB |
Output is correct |
| 2 |
Correct |
871 ms |
48492 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2076 ms |
49924 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2100 ms |
58784 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2103 ms |
80220 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
2051 ms |
74808 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
386 ms |
131072 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
381 ms |
131076 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
