Submission #366517

#	Time	Username	Problem	Language	Result	Execution time	Memory
366517		YJU	Beads and wires (APIO14_beads)	C++14	0 / 100	4 ms	4972 KiB

beads

#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector,Ofast")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=2e5+5;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()

vector<pll> v[N];
ll dp[N][2],n,x,y,c;

void DFS(ll nd,ll pa,ll pac){
	vector<ll> vec;
	ll sum=0;
	for(auto i:v[nd]){
		if(i.X!=pa){
			DFS(i.X,nd,i.Y);
			sum+=dp[i.X][0];
			vec.pb(dp[i.X][1]-dp[i.X][0]+i.Y);
		}
	}
	sort(vec.rbegin(),vec.rend());
	dp[nd][1]=(SZ(vec)>1?sum+vec[0]+vec[1]:0LL);
	dp[nd][0]=max(dp[nd][1],(SZ(vec)>0?sum+vec[0]+pac:0LL));
}

int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	cin>>n;
	REP1(i,n-1){
		cin>>x>>y>>c;
		v[x].pb(mp(y,c));
		v[y].pb(mp(x,c));
	}
	DFS(1,0,0);
	cout<<dp[1][1]<<"\n";
	return 0;
}
/*
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
*/

• Subtask 1: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43