Submission #439656

#	Time	Username	Problem	Language	Result	Execution time	Memory
439656		soroush	Beads and wires (APIO14_beads)	C++17	28 / 100	1086 ms	1100 KiB

beads

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int , int> pii;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int maxn = 1e4 + 10;
const ll mod = 1e9+7;

#define pb push_back
#define endl '\n'
#define dokme(x) cout << x , exit(0)
#define ms(x , y) memset(x , y , sizeof x)
ll pw(ll a, ll b, ll md = mod){ll res = 1;while(b){if(b&1){res=(a*res)%md;}a=(a*a)%md;b>>=1;}return(res);}

int n;
int dp[maxn][2];
vector < pii > adj[maxn];

void dfs(int v , int par = 0){
	for(auto [u , w] : adj[v])if(u ^ par)
		dfs(u , v),
		dp[v][0] += max(dp[u][0] , dp[u][1] + w);
	dp[v][1] = -2e9 - 10;
	for(auto [u , w] : adj[v])if(u ^ par)
		dp[v][1] = max(dp[v][1] , dp[v][0] + w + dp[u][0] - max(dp[u][0] , dp[u][1] + w));
}

int32_t main(){
	ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	cin >> n;
	for(int i = 1 ; i < n ; i ++){
		int a , b , c;
		cin >> a >> b >> c;
		adj[a].pb({b , c});
		adj[b].pb({a , c});
	}
	int ans = 0;
	for(int i = 1 ; i <= n ; i ++){
		ms(dp , 0) , dfs(i) , ans = max(ans , dp[i][0]);
	}
	cout << ans;
	return(0);
}

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