Submission #31611

#	Time	Username	Problem	Language	Result	Execution time	Memory
31611		huynd2001	Beads and wires (APIO14_beads)	C++14	0 / 100	10 ms	9728 KiB

beads

/*huypheu
10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/

#include <bits/stdc++.h>
#define int long long
#define oo (LLONG_MAX/2)
using namespace std;

int dp[200007][2];
vector <pair<int,int> > ch[200007],v[200007];
int par[200007];
bool vst[200007];

void dfs(int u)
{
	vst[u]=1;
	for(int i=0;i<v[u].size();i++)
	{
		int k=v[u][i].first;
		if(!vst[k])
		{
			ch[u].push_back(v[u][i]);
			par[k]=u;
			dfs(k);
		}
	}
	return ;
}

void get_ans(int u)
{
	for(int i=0;i<ch[u].size();i++)
	{
		int k=ch[u][i].first;
		get_ans(k);
	}
	dp[u][1]=-oo;
	int tot=0;
	vector <int> jo;
	for(int i=0;i<ch[u].size();i++)
	{
		int k=ch[u][i].first;
		tot+=max(dp[k][0],dp[k][1]+ch[u][i].second);
		jo.push_back(max(dp[k][0],dp[k][1]+ch[u][i].second));
	}
	for(int i=0;i<jo.size();i++)
	{
		int k=ch[u][i].first;
		dp[u][1]=max(dp[u][1],tot-jo[i]+dp[k][0]+ch[u][i].second);
	}
	// for(int i=0;i<jo.size();i++)
	// {
	// 	cout << jo[i] << " ";
	// }
	// cout << endl;
	dp[u][0]=tot;
	priority_queue <int> que;
	for(int i=0;i<jo.size();i++)
	{
		int k=ch[u][i].first;
		que.push(dp[k][0]+ch[u][i].second-jo[i]);
	}
	int ma=0;
	if(que.size()>=2)
	{
		ma+=que.top();que.pop();
		ma+=que.top();que.pop();
	}
	dp[u][0]=max(dp[u][0],dp[u][0]+ma);
	return ;
}

signed main()
{
	int n;
	cin >> n;
	for(int i=1;i<n;i++)
	{
		int a,b,c;
		cin >> a >> b >> c;
		v[a].push_back(make_pair(b,c));
		v[b].push_back(make_pair(a,c));
	}
	dfs(1);
	get_ans(1);
	// for(int i=1;i<=n;i++) cout << dp[i][0] << " " << dp[i][1] << endl;
	// cout << "concak" << endl;
	cout << dp[1][0] << endl;
	return 0;
}

Compilation message (stderr)

beads.cpp: In function 'void dfs(long long int)':
beads.cpp:27:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<v[u].size();i++)
              ~^~~~~~~~~~~~
beads.cpp: In function 'void get_ans(long long int)':
beads.cpp:42:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<ch[u].size();i++)
              ~^~~~~~~~~~~~~
beads.cpp:50:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<ch[u].size();i++)
              ~^~~~~~~~~~~~~
beads.cpp:56:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<jo.size();i++)
              ~^~~~~~~~~~
beads.cpp:68:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<jo.size();i++)
              ~^~~~~~~~~~

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