제출 #734450

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
734450		Abrar_Al_Samit	구슬과 끈 (APIO14_beads)	C++17	0 / 100	4 ms	6552 KiB

beads

#include<bits/stdc++.h>
using namespace std;


const int nax = 200005;

vector<pair<int,int>>g[nax];

int dp[nax][2], n;

int solve(int v, int topar, int p = -1) {
	int &ret = dp[v][(topar>0)];
	if(ret!=-1) return ret;
	ret = 0;

	int base = 0;
	for(auto [u, w] : g[v]) if(u!=p) {
		base += solve(u, w, v);
	}

	ret = base;


	vector<int>lap;
	for(auto [u, w] : g[v]) if(u!=p) {
		lap.push_back(-solve(u, w, v) + solve(u, 0, v) + w);
	}
	sort(lap.rbegin(), lap.rend());

	for(int i=0, acc=0; i<min(2, (int)lap.size()); ++i) {
		acc += lap[i];
		if((~i&1) && topar) {
			ret = max(ret, base + acc + topar);
		} else if(i&1) {
			ret = max(ret, base + acc);
		}
	}
	return ret;
}
void PlayGround() {
	cin>>n;
	for(int i=1; i<n; ++i) {
		int u, v, w;
		cin>>u>>v>>w;
		g[u].emplace_back(v, w);
		g[v].emplace_back(u, w);
	}	

	memset(dp, -1, sizeof dp);
	cout<<solve(1, 0)<<'\n';

	// cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
}
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	PlayGround();
	return 0;
}

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