Submission #717211

#	Time	Username	Problem	Language	Result	Execution time	Memory
717211		Obada_Saleh	Beads and wires (APIO14_beads)	C++14	0 / 100	3 ms	4964 KiB

beads

#include <bits/stdc++.h>
using namespace std;
int n;
vector<pair<long long,int>>adj[200010];
long long dp1[200010],dp2[200010],dp3[200010],dp4[200010];
bool comp(pair<int,int>x,pair<int,int>y)
{
    return x.first+dp3[x.second]-dp4[x.second]>y.first+dp3[y.second]-dp4[y.second];
}
void dfs(int node=1,int p=0)
{
    for(int i=0;i<adj[node].size();i++)
    {
        int neighbour=adj[node][i].second;
        if(neighbour==p)
        {
            adj[node].erase(adj[node].begin()+i);
            break;
        }
    }
    for(int i=0;i<adj[node].size();i++)
    {
        int neighbour=adj[node][i].second;
        dfs(neighbour,node);
    }
    for(int i=0;i<adj[node].size();i++)
    {
        int weight=adj[node][i].first;
        int neighbour=adj[node][i].second;
        dp4[neighbour]=dp3[neighbour];
        if(dp1[neighbour]!=0)
            dp4[neighbour]=max(dp4[neighbour],weight+dp1[neighbour]);
    }
    sort(adj[node].begin(),adj[node].end(),comp);
    if(adj[node].size()!=0)
    {
        int weight=adj[node][0].first;
        int neighbour=adj[node][0].second;
        dp1[node]=weight+dp3[neighbour];
        for(int i=1;i<adj[node].size();i++)
        {
            weight=adj[node][i].first;
            neighbour=adj[node][i].second;
            dp1[node]+=dp4[neighbour];
        }
    }
    if(adj[node].size()>=2)
    {
        int weight,neighbour;
        for(int i=0;i<2;i++)
        {
            weight=adj[node][i].first;
            neighbour=adj[node][i].second;
            dp2[node]+=weight+dp3[neighbour];
        }
        for(int i=2;i<adj[node].size();i++)
        {
            weight=adj[node][i].first;
            neighbour=adj[node][i].second;
            dp2[node]+=dp4[neighbour];
        }
    }
    for(int i=0;i<adj[node].size();i++)
    {
        int weight=adj[node][i].first;
        int neighbour=adj[node][i].second;
        dp3[node]+=dp4[node];
    }
    dp3[node]=max(dp3[node],dp2[node]);
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n;
    for(int i=1;i<=n-1;i++)
    {
        int u,v;
        cin>>u>>v;
        int w;
        cin>>w;
        adj[u].push_back({w,v});
        adj[v].push_back({w,u});
    }
    dfs();
    cout<<dp3[1];
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:12:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for(int i=0;i<adj[node].size();i++)
      |                 ~^~~~~~~~~~~~~~~~~
beads.cpp:21:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |     for(int i=0;i<adj[node].size();i++)
      |                 ~^~~~~~~~~~~~~~~~~
beads.cpp:26:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |     for(int i=0;i<adj[node].size();i++)
      |                 ~^~~~~~~~~~~~~~~~~
beads.cpp:40:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |         for(int i=1;i<adj[node].size();i++)
      |                     ~^~~~~~~~~~~~~~~~~
beads.cpp:56:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |         for(int i=2;i<adj[node].size();i++)
      |                     ~^~~~~~~~~~~~~~~~~
beads.cpp:63:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |     for(int i=0;i<adj[node].size();i++)
      |                 ~^~~~~~~~~~~~~~~~~
beads.cpp:65:13: warning: unused variable 'weight' [-Wunused-variable]
   65 |         int weight=adj[node][i].first;
      |             ^~~~~~
beads.cpp:66:13: warning: unused variable 'neighbour' [-Wunused-variable]
   66 |         int neighbour=adj[node][i].second;
      |             ^~~~~~~~~

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