Submission #162286

#	Time	Username	Problem	Language	Result	Execution time	Memory
162286		amoo_safar	Beads and wires (APIO14_beads)	C++14	28 / 100	1081 ms	12408 KiB

beads

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
typedef pair<pll, pll> node;
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

const ll Mod = 1000000007LL;
const int Maxn = 3e5 + 10;
const int Maxk = 60;
const ll Inf = 2242545357980376863LL;
const ll Log = 30;

vector<pll> G[Maxn];

ll dp1[Maxn], dp2[Maxn];

ll DFS(ll u, ll p){
	ll adj;
	ll mx = -Inf;
	for(auto ed : G[u]){
		adj = ed.F;
		if(adj == p) continue;
		DFS(adj, u);
		dp1[u] += max(dp1[adj], dp2[adj] + ed.S);
		mx = max(mx, ed.S + dp1[adj] - max(dp1[adj], dp2[adj] + ed.S));
	}
	dp2[u] = dp1[u] + mx;
}

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	ll n;
	cin >> n;
	ll u, v, w;
	for(int i = 1; i < n; i++){
		cin >> u >> v >> w;
		G[u].pb({v, w});
		G[v].pb({u, w});
	}
	ll ans = 0;
	for(int i = 1; i <= n; i++){
		memset(dp1, 0, sizeof dp1);
		memset(dp2, 0, sizeof dp2);
		DFS(i, -1);
		ans = max(ans, dp1[i]);
	}
	cout << ans;
	return 0;
}
/*
5
1 2 10
1 3 40
1 4 15
1 5 20

*/

Compilation message (stderr)

beads.cpp: In function 'll DFS(ll, ll)':
beads.cpp:41:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^

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