//#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<int,llo>> adj[1000001];
vector<pair<int,llo>> adj2[1000001];
int par[1000001];
int find(int 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<int,llo>> pp;
vector<pair<int,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();
}
}
}
bool 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<int,int>,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<int,int>,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;
/* while(true){
continue;
}*/
//cout<<cost<<":"<<endl;
continue;
}
maa=0;
for(auto i:tt){
for(auto k:adj[i]){
if(vis[k.a]+vis[i]<2){
adj2[i].pb(k);
}
else{
}
}
}
for(auto i:pp){
dfs2(i.a);
}
cost=max(cost,maa);
vector<pair<int,llo>> pp2=pp;
for(auto i:pp){
pp2.pb(i);
}
llo xx=pp.size();
multiset<llo> zz;
vector<llo> xd;
llo su2=0;
/*for(auto i:pp2){
cout<<i.a<<"<"<<i.b<<endl;
}*/
for(llo i=0;i<pp2.size();i++){
if(i>=xx){
auto jj=zz.find(xd[i-xx]);
zz.erase(jj);
}
su2+=pp2[i].b;
if(zz.size()){
auto jj=zz.end();
jj--;
cost=max(cost,dp[pp2[i].a][0]+su2+(*jj));
}
xd.pb(dp[pp2[i].a][0]-su2);
zz.insert(xd.back());
}
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:199:16: warning: comparison of integer expressions of different signedness: 'llo' {aka 'long long int'} and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
199 | for(llo i=0;i<pp2.size();i++){
| ~^~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
35 ms |
47340 KB |
Output is correct |
| 2 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 3 |
Correct |
30 ms |
47468 KB |
Output is correct |
| 4 |
Correct |
37 ms |
47340 KB |
Output is correct |
| 5 |
Correct |
30 ms |
47340 KB |
Output is correct |
| 6 |
Correct |
34 ms |
47340 KB |
Output is correct |
| 7 |
Correct |
32 ms |
47340 KB |
Output is correct |
| 8 |
Correct |
34 ms |
47340 KB |
Output is correct |
| 9 |
Correct |
33 ms |
47340 KB |
Output is correct |
| 10 |
Correct |
35 ms |
47340 KB |
Output is correct |
| 11 |
Correct |
30 ms |
47340 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
35 ms |
47596 KB |
Output is correct |
| 2 |
Correct |
31 ms |
47468 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
31 ms |
47596 KB |
Output is correct |
| 2 |
Correct |
38 ms |
48236 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
43 ms |
49516 KB |
Output is correct |
| 2 |
Correct |
63 ms |
55012 KB |
Output is correct |
| 3 |
Correct |
56 ms |
50152 KB |
Output is correct |
| 4 |
Correct |
38 ms |
48748 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
80 ms |
58076 KB |
Output is correct |
| 2 |
Correct |
95 ms |
60008 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
164 ms |
77484 KB |
Output is correct |
| 2 |
Correct |
209 ms |
87652 KB |
Output is correct |
| 3 |
Correct |
255 ms |
111648 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
275 ms |
90384 KB |
Output is correct |
| 2 |
Runtime error |
296 ms |
131076 KB |
Execution killed with signal 9 |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
384 ms |
131076 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
387 ms |
131076 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
