#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=2e5+5;
int n;
vector<pair<int,int>> adj[N];
ll dp[N][4];
void dfs(int u,int p=0){
pair<pair<ll,int>,pair<ll,int>> mx={{-1e18,-1},{-1e18,-1}},mx2={{-1e18,-1},{-1e18,-1}};
for(auto [v,w]:adj[u]){
if(v==p)continue;
dfs(v,u);
ll res=max({dp[v][0],dp[v][1],dp[v][2]+w});
dp[u][0]+=max(res,dp[v][3]+w);
dp[u][1]+=res;
dp[u][2]+=res;
dp[u][3]+=res;
mx.second=max(mx.second,{dp[v][0]+w-res,v});
if(mx.second>mx.first)swap(mx.first,mx.second);
mx2.second=max(mx2.second,{max(dp[v][0],dp[v][1])+w-res,v});
if(mx2.second>mx2.first)swap(mx2.first,mx2.second);
}
ll c1=mx.first.first+max(mx.second.first,mx.first.second!=mx2.first.second?mx2.first.first:mx2.second.first);
ll c2=mx2.first.first+(mx2.first.second!=mx.first.second?mx.first.first:mx.second.first);
dp[u][1]+=max(c1,c2);
dp[u][2]+=mx.first.first;
dp[u][3]+=max(mx.first.first,mx2.first.first);
}
int main(){
cin.tie(nullptr)->sync_with_stdio(false);
cin >> n;
for(int i=1;i<n;i++){
int u,v,w;
cin >> u >> v >> w;
adj[u].emplace_back(v,w);
adj[v].emplace_back(u,w);
}
dfs(1);
cout << max(dp[1][0],dp[1][1]);
}
Compilation message
beads.cpp: In function 'void dfs(int, int)':
beads.cpp:15:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
15 | for(auto [v,w]:adj[u]){
| ^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 2 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 3 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 4 |
Correct |
2 ms |
4948 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 6 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 7 |
Correct |
3 ms |
5016 KB |
Output is correct |
| 8 |
Correct |
3 ms |
5028 KB |
Output is correct |
| 9 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 10 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 11 |
Correct |
3 ms |
5008 KB |
Output is correct |
| 12 |
Correct |
3 ms |
4948 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 2 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 3 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 4 |
Correct |
2 ms |
4948 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 6 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 7 |
Correct |
3 ms |
5016 KB |
Output is correct |
| 8 |
Correct |
3 ms |
5028 KB |
Output is correct |
| 9 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 10 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 11 |
Correct |
3 ms |
5008 KB |
Output is correct |
| 12 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 13 |
Incorrect |
3 ms |
4948 KB |
Output isn't correct |
| 14 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 2 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 3 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 4 |
Correct |
2 ms |
4948 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 6 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 7 |
Correct |
3 ms |
5016 KB |
Output is correct |
| 8 |
Correct |
3 ms |
5028 KB |
Output is correct |
| 9 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 10 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 11 |
Correct |
3 ms |
5008 KB |
Output is correct |
| 12 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 13 |
Incorrect |
3 ms |
4948 KB |
Output isn't correct |
| 14 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 2 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 3 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 4 |
Correct |
2 ms |
4948 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 6 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 7 |
Correct |
3 ms |
5016 KB |
Output is correct |
| 8 |
Correct |
3 ms |
5028 KB |
Output is correct |
| 9 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 10 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 11 |
Correct |
3 ms |
5008 KB |
Output is correct |
| 12 |
Correct |
3 ms |
4948 KB |
Output is correct |
| 13 |
Incorrect |
3 ms |
4948 KB |
Output isn't correct |
| 14 |
Halted |
0 ms |
0 KB |
- |
