Submission #957366

#	Time	Username	Problem	Language	Result	Execution time	Memory
957366		vjudge1	Beads and wires (APIO14_beads)	C++14	0 / 100	2 ms	4956 KiB

beads

#include<bits/stdc++.h>

using namespace std;

const int N=2e5+10;
int f[N][2];
vector<pair<int, int>> g[N];

void dfs(int u, int p){
   for (auto &e:g[u]) if (e.first!=p) dfs(e.first, u);
   vector<int> vv;
   int sum=0;
   for (auto &e:g[u]){
      int v=e.first, w=e.second;
      if (v==p) continue;
      sum+=max(f[v][0], f[v][1]), vv.push_back(f[v][0]+w-max(f[v][0], f[v][1]));
   }
   sort(vv.rbegin(), vv.rend());
   vector<int> pf=vv;
   partial_sum(vv.begin(), vv.end(), pf.begin());
   f[u][0]=sum;
   for (int j=1; j<(int)pf.size(); j+=2) f[u][0]=max(f[u][0], sum+pf[j]);
   if (p && (int)g[u].size()>1){
      int wpar=0;
      for (auto &e:g[p]) if (e.first==u) wpar=e.second;
      for (int j=0; j<(int)pf.size(); j+=2) f[u][1]=max(f[u][1], sum+pf[j]+wpar);
   }
}

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   int n;
   cin >> n;
   for (int i=1; i<n; ++i){
      int u, v, w; cin >> u >> v >> w;
      g[u].emplace_back(v, w);
      g[v].emplace_back(u, w);
   }
   dfs(1, 0);
   cout << f[1][0];
   return 0;
}

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