Submission #33970

#	Time	Username	Problem	Language	Result	Execution time	Memory
33970		mohammad_kilani	Beads and wires (APIO14_beads)	C++14	0 / 100	11 ms	9728 KiB

beads

#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define oo 2000000000
const int N = 300010;
int n , dp[N][2];
vector< pair<int,int> > g[N];

int solve(int node,int prnt,int len,bool b){
	if(dp[node][b] != -1) return dp[node][b];
	int sum = 0 ;
	dp[node][b] = 0 ;
	vector<int> v;
	for(int i=0;i<g[node].size();i++){
		if(g[node][i].first != prnt){
			int cur = solve(g[node][i].first,node,g[node][i].second,0);
			int cur2 = solve(g[node][i].first,node,g[node][i].second,1);
			sum += cur2;
			v.push_back(cur - cur2 + g[node][i].second);
		}
	}
	dp[node][b] = sum;
	sort(v.begin(),v.end());
	if(v.size() > 1) dp[node][b] = max(dp[node][b],v[v.size()-1] + v[v.size()-2] + sum);
	if(b){ 
		if(v.size() > 2)
			dp[node][b] = max(dp[node][b],sum + len + v[v.size()-1] + v[v.size()-2] + v[v.size()-3]);
		else if(v.size() > 0)
			dp[node][b] = max(dp[node][b],sum + len + v[v.size()-1]);
	}
	return dp[node][b];
}

int main() {
	//freopen("in.txt","r",stdin);
	scanf("%d",&n);
	for(int i=0;i<n-1;i++){
		int u , v, w;
		scanf("%d%d%d",&u,&v,&w);
		g[u].push_back(make_pair(v,w));
		g[v].push_back(make_pair(u,w));
	}
	memset(dp,-1,sizeof(dp));
	cout<< solve(1,-1,0,0) << endl;
	return 0;
}

Compilation message (stderr)

beads.cpp: In function 'int solve(int, int, int, bool)':
beads.cpp:14:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<g[node].size();i++){
              ~^~~~~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:36:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
beads.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d",&u,&v,&w);
   ~~~~~^~~~~~~~~~~~~~~~~~~

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