#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef double db;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<db,db> pdb;
typedef tuple<int,int,int> tii;
typedef vector<vector<ll>> mat;
const ll mod=1e9+7;
const int N=2e5+5;
int n,ans,dp1[N],dp2[N],dp3[N],dp4[N],val[N];
vector<pii> g[N];
//dp1 : 없/끝, dp2 : 없/부모로, dp3 : 있/끝, dp4 : 있/부모로
void dfs(int x,int p){
vector<int> v;
dp2[x]=dp3[x]=dp4[x]=-1e9;
int s=0;
for(auto &it : g[x]) if(it.fi!=p){
int u=it.fi,c=it.se;
dfs(u,x);
val[u]=max(dp1[u],dp2[u]+c);
dp1[x]+=max(dp1[u],dp2[u]+c);
v.emplace_back(dp1[u]-val[u]+c);
s+=val[u];
}
sort(v.begin(),v.end()); reverse(v.begin(),v.end());
for(auto &it : g[x]) if(it.fi!=p){
int u=it.fi,c=it.se;
dp2[x]=max(dp2[x],dp1[x]-val[u]+dp1[u]+c);
dp3[x]=max(dp3[x],dp1[x]-val[u]+max(dp3[u],dp4[u]+c));
dp4[x]=max(dp4[x],dp1[x]-val[u]+dp3[u]+c);
}
if(v.size()>=2){
for(auto &it : g[x]) if(it.fi!=p){
int u=it.fi,c=it.se;
if(dp1[u]-val[u]+c==v[0]) dp3[x]=max(dp3[x],dp1[x]-val[u]+max(dp1[u],dp3[u])+c+v[1]);
else dp3[x]=max(dp3[x],dp1[x]-val[u]+max(dp1[u],dp3[u])+c+v[0]);
}
}
//cout<<x<<" : "<<dp1[x]<<" "<<dp2[x]<<" "<<dp3[x]<<" "<<dp4[x]<<"\n";
}
int main(){
ios::sync_with_stdio(false); cin.tie(0);
cin>>n; int s=0;
for(int u,v,c,i=1;i<n;i++){
cin>>u>>v>>c;
s+=c;
g[u].emplace_back(v,c);
g[v].emplace_back(u,c);
}
dfs(1,0);
cout<<max(dp1[1],dp3[1]);
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
4984 KB |
Output is correct |
3 |
Correct |
6 ms |
4856 KB |
Output is correct |
4 |
Correct |
11 ms |
5112 KB |
Output is correct |
5 |
Correct |
4 ms |
4984 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
7 ms |
4856 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
8 ms |
5112 KB |
Output is correct |
10 |
Correct |
6 ms |
4984 KB |
Output is correct |
11 |
Correct |
6 ms |
4988 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
4984 KB |
Output is correct |
3 |
Correct |
6 ms |
4856 KB |
Output is correct |
4 |
Correct |
11 ms |
5112 KB |
Output is correct |
5 |
Correct |
4 ms |
4984 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
7 ms |
4856 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
8 ms |
5112 KB |
Output is correct |
10 |
Correct |
6 ms |
4984 KB |
Output is correct |
11 |
Correct |
6 ms |
4988 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
13 |
Correct |
7 ms |
5112 KB |
Output is correct |
14 |
Correct |
7 ms |
5112 KB |
Output is correct |
15 |
Correct |
6 ms |
5112 KB |
Output is correct |
16 |
Correct |
6 ms |
5112 KB |
Output is correct |
17 |
Correct |
6 ms |
4984 KB |
Output is correct |
18 |
Correct |
7 ms |
5116 KB |
Output is correct |
19 |
Correct |
7 ms |
5112 KB |
Output is correct |
20 |
Correct |
6 ms |
4984 KB |
Output is correct |
21 |
Correct |
4 ms |
4984 KB |
Output is correct |
22 |
Correct |
7 ms |
5112 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
4984 KB |
Output is correct |
3 |
Correct |
6 ms |
4856 KB |
Output is correct |
4 |
Correct |
11 ms |
5112 KB |
Output is correct |
5 |
Correct |
4 ms |
4984 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
7 ms |
4856 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
8 ms |
5112 KB |
Output is correct |
10 |
Correct |
6 ms |
4984 KB |
Output is correct |
11 |
Correct |
6 ms |
4988 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
13 |
Correct |
7 ms |
5112 KB |
Output is correct |
14 |
Correct |
7 ms |
5112 KB |
Output is correct |
15 |
Correct |
6 ms |
5112 KB |
Output is correct |
16 |
Correct |
6 ms |
5112 KB |
Output is correct |
17 |
Correct |
6 ms |
4984 KB |
Output is correct |
18 |
Correct |
7 ms |
5116 KB |
Output is correct |
19 |
Correct |
7 ms |
5112 KB |
Output is correct |
20 |
Correct |
6 ms |
4984 KB |
Output is correct |
21 |
Correct |
4 ms |
4984 KB |
Output is correct |
22 |
Correct |
7 ms |
5112 KB |
Output is correct |
23 |
Correct |
9 ms |
5368 KB |
Output is correct |
24 |
Correct |
9 ms |
5368 KB |
Output is correct |
25 |
Correct |
10 ms |
5368 KB |
Output is correct |
26 |
Correct |
13 ms |
5624 KB |
Output is correct |
27 |
Correct |
12 ms |
5596 KB |
Output is correct |
28 |
Correct |
12 ms |
5752 KB |
Output is correct |
29 |
Correct |
12 ms |
5624 KB |
Output is correct |
30 |
Correct |
12 ms |
5624 KB |
Output is correct |
31 |
Correct |
13 ms |
6264 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
4984 KB |
Output is correct |
3 |
Correct |
6 ms |
4856 KB |
Output is correct |
4 |
Correct |
11 ms |
5112 KB |
Output is correct |
5 |
Correct |
4 ms |
4984 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
7 ms |
4856 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
8 ms |
5112 KB |
Output is correct |
10 |
Correct |
6 ms |
4984 KB |
Output is correct |
11 |
Correct |
6 ms |
4988 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
13 |
Correct |
7 ms |
5112 KB |
Output is correct |
14 |
Correct |
7 ms |
5112 KB |
Output is correct |
15 |
Correct |
6 ms |
5112 KB |
Output is correct |
16 |
Correct |
6 ms |
5112 KB |
Output is correct |
17 |
Correct |
6 ms |
4984 KB |
Output is correct |
18 |
Correct |
7 ms |
5116 KB |
Output is correct |
19 |
Correct |
7 ms |
5112 KB |
Output is correct |
20 |
Correct |
6 ms |
4984 KB |
Output is correct |
21 |
Correct |
4 ms |
4984 KB |
Output is correct |
22 |
Correct |
7 ms |
5112 KB |
Output is correct |
23 |
Correct |
9 ms |
5368 KB |
Output is correct |
24 |
Correct |
9 ms |
5368 KB |
Output is correct |
25 |
Correct |
10 ms |
5368 KB |
Output is correct |
26 |
Correct |
13 ms |
5624 KB |
Output is correct |
27 |
Correct |
12 ms |
5596 KB |
Output is correct |
28 |
Correct |
12 ms |
5752 KB |
Output is correct |
29 |
Correct |
12 ms |
5624 KB |
Output is correct |
30 |
Correct |
12 ms |
5624 KB |
Output is correct |
31 |
Correct |
13 ms |
6264 KB |
Output is correct |
32 |
Correct |
45 ms |
7828 KB |
Output is correct |
33 |
Correct |
42 ms |
7944 KB |
Output is correct |
34 |
Correct |
43 ms |
7948 KB |
Output is correct |
35 |
Correct |
242 ms |
16548 KB |
Output is correct |
36 |
Correct |
250 ms |
16608 KB |
Output is correct |
37 |
Correct |
243 ms |
16476 KB |
Output is correct |
38 |
Correct |
175 ms |
18532 KB |
Output is correct |
39 |
Correct |
171 ms |
20696 KB |
Output is correct |
40 |
Correct |
178 ms |
21176 KB |
Output is correct |
41 |
Correct |
250 ms |
26328 KB |
Output is correct |