#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define int ll
#define pii pair<int, int>
#define f first
#define s second
#define REP(i,n) for (int i = 0; i<n; ++i)
#ifdef BALBIT
#define bug(...) cerr<<"#"<<__LINE__<<": "<<#__VA_ARGS__<<": ", _do(__VA_ARGS__)
template<typename T> void _do(T && x){cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y){cerr<<x<<", "; _do(y...);}
#define IOS()
#else
#define IOS() ios::sync_with_stdio(0), cin.tie(0)
#define endl '\n'
#define bug(...)
#endif // BALBIT
#define SZ(x) (int)(x.size())
#define ALL(x) (x).begin(), (x).end()
#define pb push_back
const int maxn = 2e5+5;
vector<pii> g[maxn];
ll dp[maxn][2];
void dfs(int v, int p, ll w) {
vector<ll> mo;
ll sg = 0;
for (pii u : g[v]) {
if (u.f == p) continue;
dfs(u.f,v,u.s);
mo.pb(dp[u.f][0] - dp[u.f][1] + u.s);
sg += dp[u.f][1];
}
sort(ALL(mo), greater<ll>());
dp[v][0] = sg;
if (SZ(mo) >= 2) {
dp[v][0] = max(dp[v][0], sg + mo[0] + mo[1]);
}
dp[v][1] = dp[v][0];
if (SZ(mo) >= 1) {
dp[v][1] = max(dp[v][1], sg + mo[0] + w);
}
}
signed main(){
IOS();
int n; cin>>n;
for (int i = 0; i<n-1; ++i) {
int a,b,w; cin>>a>>b>>w;
--a;--b;g[a].pb({b,w});g[b].pb({a,w});
}
dfs(0,-1,0);
cout<<dp[0][0]<<endl;
}
/*
10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
4992 KB |
Output is correct |
2 |
Correct |
7 ms |
4992 KB |
Output is correct |
3 |
Correct |
8 ms |
4992 KB |
Output is correct |
4 |
Correct |
7 ms |
5120 KB |
Output is correct |
5 |
Correct |
8 ms |
5120 KB |
Output is correct |
6 |
Incorrect |
7 ms |
4992 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
4992 KB |
Output is correct |
2 |
Correct |
7 ms |
4992 KB |
Output is correct |
3 |
Correct |
8 ms |
4992 KB |
Output is correct |
4 |
Correct |
7 ms |
5120 KB |
Output is correct |
5 |
Correct |
8 ms |
5120 KB |
Output is correct |
6 |
Incorrect |
7 ms |
4992 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
4992 KB |
Output is correct |
2 |
Correct |
7 ms |
4992 KB |
Output is correct |
3 |
Correct |
8 ms |
4992 KB |
Output is correct |
4 |
Correct |
7 ms |
5120 KB |
Output is correct |
5 |
Correct |
8 ms |
5120 KB |
Output is correct |
6 |
Incorrect |
7 ms |
4992 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
4992 KB |
Output is correct |
2 |
Correct |
7 ms |
4992 KB |
Output is correct |
3 |
Correct |
8 ms |
4992 KB |
Output is correct |
4 |
Correct |
7 ms |
5120 KB |
Output is correct |
5 |
Correct |
8 ms |
5120 KB |
Output is correct |
6 |
Incorrect |
7 ms |
4992 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |