Submission #31621

#	Time	Username	Problem	Language	Result	Execution time	Memory
31621		cheater2k	Beads and wires (APIO14_beads)	C++14	28 / 100	1076 ms	5248 KiB

beads

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

const int N = 200010;
const int inf = 2e9 + 12345;

int n;
int f[N][2];
vector < pair<int,int> > G[N];
int ans;

void dfs(int u, int p) {
	vector < pair<int,int> > ch;
	for (auto edge: G[u]) if (edge.second != p) {
		dfs(edge.second, u);
		ch.push_back(edge);
	}
	f[u][1] = -inf;
	f[u][0] = 0;
	for (auto edge: ch) {
		f[u][0] += max(f[edge.second][0], f[edge.second][1] + edge.first);
	}
	for (auto edge: ch) {
		int mx = f[u][0];
		mx -= max(f[edge.second][0], f[edge.second][1] + edge.first);
		mx += (f[edge.second][0] + edge.first);
		f[u][1] = max(f[u][1], mx);
	}
}

void re_dfs(int u, int p) {
	for (auto edge: G[u]) if (edge.second != p) {
		
	}
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n;
	for (int i = 1; i < n; ++i) {
		int u, v, w; cin >> u >> v >> w;
		G[u].push_back(make_pair(w,v)); G[v].push_back(make_pair(w,u));
	}

	for (int i = 1; i <= n; ++i) {
		dfs(i,i);
		ans = max(ans, f[i][0]);
	}

	cout << ans << endl;
}

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