Submission #298750

#	Time	Username	Problem	Language	Result	Execution time	Memory
298750		errorgorn	Beads and wires (APIO14_beads)	C++14	28 / 100	1052 ms	7964 KiB

beads

//雪花飄飄北風嘯嘯
//天地一片蒼茫

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl

#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()

#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

int n;
vector<ii> al[200005];
map<ii,ii> memo;

ii dp(int i,int p){
	if (memo.count(ii(i,p))) return memo[ii(i,p)];
	
	ll total=0;
	vector<int> v={(int)-1e9};
	for (auto &it:al[i]){
		if (it.fi==p) continue;
		
		auto temp=dp(it.fi,i);
		ll val=max(temp.fi,temp.se+it.se);
		
		total+=val;
		v.push_back(temp.fi+it.se-val);
	}
	
	sort(all(v));
	
	return memo[ii(i,p)]=ii(total,total+v.back());
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin.exceptions(ios::badbit | ios::failbit);
	
	cin>>n;
	
	int a,b,c;
	rep(x,1,n){
		cin>>a>>b>>c;
		
		al[a].push_back(ii(b,c));
		al[b].push_back(ii(a,c));
	}
	
	ll ans=0;
	rep(x,1,n+1) ans=max(ans,dp(x,-1).fi);
	
	cout<<ans<<endl;
}

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