Submission #412737

#	Time	Username	Problem	Language	Result	Execution time	Memory
412737		LastRonin	Beads and wires (APIO14_beads)	C++14	28 / 100	1077 ms	972 KiB

beads

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define ll long long
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define pill pair<ll, ll>
using namespace std;
 
const ll N = 1e4 + 10;
const ll big = 1e9;
 
ll n;
vector<pair<int,int>> g[N];
int dp2[N][3];
int ans;
 
void dfs(int v, int p, int z) {	
	dp2[v][0] = 0, dp2[v][1] = -big, dp2[v][2] = -big;
	for(auto u : g[v]) {
		if(u.f != p) { 
			dfs(u.f, v, u.s);
			int z = max(dp2[u.f][0], dp2[u.f][1] + u.s);
			dp2[v][2] = max(dp2[v][2] + z, dp2[v][1] + dp2[u.f][0] + u.s);
			dp2[v][1] = max(dp2[v][1] + z, dp2[v][0] + dp2[u.f][0] + u.s);
			dp2[v][0] = dp2[v][0] + z;
		}
	}
	ans = max(ans, dp2[v][2]);
}
 
int main() {
	speed;
	cin >> n;
	for(int i = 1, a, b, c; i < n; i++)
		cin >> a >> b >> c, g[a].pb(mp(b, c)), g[b].pb(mp(a, c));
	for(int i = 1; i <= n; i++)
		dfs(i, 0, 0);
	cout << ans;
}

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