Submission #257472

#	Time	Username	Problem	Language	Result	Execution time	Memory
257472		Evirir	Beads and wires (APIO14_beads)	C++17	0 / 100	4 ms	4992 KiB

beads

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define setp(x) cout<<fixed<<setprecision(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define pqueue priority_queue
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;
typedef long double ld;
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> pbds;
void amin(ll &a, ll b){ a=min(a,b); }
void amax(ll &a, ll b){ a=max(a,b); }
void YES(){cout<<"YES\n";} void NO(){cout<<"NO\n";}
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
const ll INF = ll(1e18);
const int MOD = 998244353;

const bool DEBUG = 0;
const int MAXN = 200005;

int n;
vii adj[MAXN];
ll dp[MAXN][2],top[MAXN];

void dfs(int u, int p)
{
	ll sum=0;
	vi diff;
	for(ii tmp: adj[u])
	{
		int v=tmp.F; ll w=tmp.S;
		if(v==p) continue;
		top[v]=w;
		
		dfs(v,u);
		
		sum+=max(dp[v][0],dp[v][1]);
		diff.pb(-max(dp[v][0],dp[v][1])+dp[v][0]+w);
	}
	
	sort(diff.begin(), diff.end(), greater<ll>());
	
	if(diff.size()>=1) dp[u][1]=top[u]+sum+diff[0];
	dp[u][0]=sum;
	if(diff.size()>=2) dp[u][0]=max(dp[u][0], sum+diff[0]+diff[1]);
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	
	cin>>n;
	
	if(n<=2)
	{
		cout<<0<<'\n';
		return 0;
	}
	
	forn(i,0,n-1)
	{
		int u,v; ll w; cin>>u>>v>>w; u--; v--;
		adj[u].pb({v,w});
		adj[v].pb({u,w});
	}
	
	dfs(0,-1);
	cout<<dp[0][0]<<'\n';
	
	return 0;
}

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