Submission #727151

#	Time	Username	Problem	Language	Result	Execution time	Memory
727151		ono_de206	Beads and wires (APIO14_beads)	C++14	28 / 100	1069 ms	5844 KiB

beads

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

#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define in insert
#define all(x) x.begin(),x.end()
#define pb push_back
#define eb emplace_back
#define ff first
#define ss second

#define int long long
 
typedef long long ll;
typedef vector<int> vi;
typedef set<int> si;
typedef multiset<int> msi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;

template<typename T, typename U>
ostream & operator << (ostream &out, const pair<T, U> &c) {
	out << c.first << ' ' << c.second;
    return out;
}

template<typename T>
ostream & operator << (ostream &out, vector<T> &v) {
	const int sz = v.size();
	for (int i = 0; i < sz; i++) {
		if (i) out << ' ';
		out << v[i];
	}
    return out;
}

template<typename T>
istream & operator >> (istream &in, vector<T> &v) {
	for (T &x : v) in >> x;
    return in;
}


template<typename T>
void mxx(T &a, T b){if(b > a) a = b;}
template<typename T>
void mnn(T &a, T b){if(b < a) a = b;}

const int mxn = 2e5 + 10, inf = 1e18;
int n, f[mxn], g[mxn], ans;
vector<pair<int, int>> adj[mxn];

void dfs1(int to, int fr) {
	f[to] = 0;
	g[to] = -inf;
	int mx1 = -inf;
	for(auto it : adj[to]) {
		if(it.ff == fr) continue;
		int x = it.ff;
		dfs1(x, to);
		f[to] += max(f[x], g[x] + it.ss);
		mxx(mx1, f[x] + it.ss - max(f[x], g[x] + it.ss));
	}
	mxx(g[to], f[to] + mx1);
}

void go() {
	cin >> n;
	for(int i = 1; i < n; i++) {
		int x, y, c;
		cin >> x >> y >> c;
		adj[x].eb(y, c);
		adj[y].eb(x, c);
	}
	for(int i = 1; i <= n; i++) {
		dfs1(i, 0);
		mxx(ans, f[i]);
	}
	cout << ans << '\n';
}
 
signed main() {
	//#ifndef ONO
	//freopen("beads.in", "r", stdin);
	//freopen("beads.out", "w", stdout);
	//#endif
	fast;
	int t = 1;
	// cin >> t;
	while(t--) {
		go();
	}
	return 0;
}

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