#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(long long i=0;i<(long long)(n);i++)
#define REP(i,k,n) for(long long i=k;i<(long long)(n);i++)
#define all(a) a.begin(),a.end()
#define pb emplace_back
#define eb emplace_back
#define lb(v,k) (lower_bound(all(v),k)-v.begin())
#define ub(v,k) (upper_bound(all(v),k)-v.begin())
#define fi first
#define se second
#define pi M_PI
#define PQ(T) priority_queue<T>
#define SPQ(T) priority_queue<T,vector<T>,greater<T>>
#define dame(a) {out(a);return 0;}
#define decimal cout<<fixed<<setprecision(15);
#define dupli(a) {sort(all(a));a.erase(unique(all(a)),a.end());}
typedef long long ll;
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> PP;
typedef tuple<ll,ll,ll,ll> PPP;
typedef multiset<ll> S;
using vi=vector<ll>;
using vvi=vector<vi>;
using vvvi=vector<vvi>;
using vvvvi=vector<vvvi>;
using vp=vector<P>;
using vvp=vector<vp>;
using vb=vector<bool>;
using vvb=vector<vb>;
const ll inf=1001001001001001001;
const ll INF=1001001001;
const ll mod=1000000007;
const double eps=1e-10;
template<class T> bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<class T> bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T> void out(T a){cout<<a<<'\n';}
template<class T> void outp(T a){cout<<'('<<a.fi<<','<<a.se<<')'<<'\n';}
template<class T> void outvp(T v){rep(i,v.size())cout<<'('<<v[i].fi<<','<<v[i].se<<')';cout<<'\n';}
template<class T> void outvvp(T v){rep(i,v.size())outvp(v[i]);}
template<class T> void outv(T v){rep(i,v.size()){if(i)cout<<' ';cout<<v[i];}cout<<'\n';}
template<class T> void outvv(T v){rep(i,v.size())outv(v[i]);}
template<class T> bool isin(T x,T l,T r){return (l)<=(x)&&(x)<=(r);}
template<class T> void yesno(T b){if(b)out("yes");else out("no");}
template<class T> void YesNo(T b){if(b)out("Yes");else out("No");}
template<class T> void YESNO(T b){if(b)out("YES");else out("NO");}
template<class T> void noyes(T b){if(b)out("no");else out("yes");}
template<class T> void NoYes(T b){if(b)out("No");else out("Yes");}
template<class T> void NOYES(T b){if(b)out("NO");else out("YES");}
void outs(ll a,ll b){if(a>=inf-100)out(b);else out(a);}
ll gcd(ll a,ll b){if(b==0)return a;return gcd(b,a%b);}
ll modpow(ll a,ll b){ll res=1;a%=mod;while(b){if(b&1)res=res*a%mod;a=a*a%mod;b>>=1;}return res;}
ll dp[2][2][200005];
vvp g;
void dfs(int i,int p,ll e){
ll sum=0,mx=-inf,my=-inf;
vi v;
for(auto x:g[i])if(x.fi!=p){
dfs(x.fi,i,x.se);
sum+=dp[1][0][x.fi];
v.pb(dp[0][1][x.fi]-dp[1][0][x.fi]+x.se);
chmax(mx,dp[0][0][x.fi]-dp[1][0][x.fi]);
chmax(my,dp[1][1][x.fi]-dp[1][0][x.fi]+x.se);
}
sort(all(v));reverse(all(v));
if(v.size())dp[0][0][i]=sum+v[0]+e;
if(v.size()>1)dp[0][1][i]=sum+v[0]+v[1];
chmax(dp[0][1][i],sum+mx);
chmax(dp[1][0][i],sum+my+e);
dp[1][1][i]=sum;
for(int j=1;j>=0;j--)for(int k=1;k>=0;k--){
if(j)chmax(dp[j-1][k][i],dp[j][k][i]);
if(k)chmax(dp[j][k-1][i],dp[j][k][i]);
}
// out(i);rep(j,2)rep(k,2)cout<<dp[j][k][i]<<' ';cout<<endl;
}
int main(){
ll n;cin>>n;
g=vvp(n);
rep(i,n-1){
ll a,b,c;cin>>a>>b>>c;a--;b--;
g[a].pb(b,c);g[b].pb(a,c);
}
dfs(0,-1,-inf);
out(dp[0][1][0]);
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
1 ms |
384 KB |
Output is correct |
3 |
Correct |
0 ms |
384 KB |
Output is correct |
4 |
Correct |
1 ms |
288 KB |
Output is correct |
5 |
Correct |
1 ms |
384 KB |
Output is correct |
6 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
1 ms |
384 KB |
Output is correct |
3 |
Correct |
0 ms |
384 KB |
Output is correct |
4 |
Correct |
1 ms |
288 KB |
Output is correct |
5 |
Correct |
1 ms |
384 KB |
Output is correct |
6 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
1 ms |
384 KB |
Output is correct |
3 |
Correct |
0 ms |
384 KB |
Output is correct |
4 |
Correct |
1 ms |
288 KB |
Output is correct |
5 |
Correct |
1 ms |
384 KB |
Output is correct |
6 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
1 ms |
384 KB |
Output is correct |
3 |
Correct |
0 ms |
384 KB |
Output is correct |
4 |
Correct |
1 ms |
288 KB |
Output is correct |
5 |
Correct |
1 ms |
384 KB |
Output is correct |
6 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |