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Submission #366523

# Submission time Handle Problem Language Result Execution time Memory
366523 2021-02-14T10:27:14 Z YJU Beads and wires (APIO14_beads) C++14
0 / 100
 6 ms 8172 KB 
#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector,Ofast")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=2e5+5;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()

vector<pll> v[N];
ll dp[N][2],n,x,y,c;

void DFS(ll nd,ll pa,ll pac){
	vector<ll> vec;
	ll sum=0;
	for(auto i:v[nd]){
		if(i.X!=pa){
			DFS(i.X,nd,i.Y);
			sum+=dp[i.X][0];
			vec.pb(dp[i.X][1]-dp[i.X][0]+i.Y);
		}
	}
	sort(vec.rbegin(),vec.rend());
	dp[nd][1]=(SZ(vec)>1?sum+vec[0]+vec[1]:sum);
	dp[nd][0]=max(dp[nd][1],(SZ(vec)>0?sum+vec[0]+pac:0LL));
}

int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	cin>>n;
	REP1(i,n-1){
		cin>>x>>y>>c;
		v[x].pb(mp(y,c));
		v[y].pb(mp(x,c));
	}
	ll ans=0;
	REP1(i,n){
		memset(dp,0,sizeof(dp));
		DFS(i,0,0);
		ans=max(ans,dp[i][1]);
	}
	cout<<ans<<"\n";
	return 0;
}
/*
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
*/

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 8172 KB Output is correct
2 Correct 6 ms 8172 KB Output is correct
3 Correct 6 ms 8172 KB Output is correct
4 Incorrect 6 ms 8172 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 8172 KB Output is correct
2 Correct 6 ms 8172 KB Output is correct
3 Correct 6 ms 8172 KB Output is correct
4 Incorrect 6 ms 8172 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 8172 KB Output is correct
2 Correct 6 ms 8172 KB Output is correct
3 Correct 6 ms 8172 KB Output is correct
4 Incorrect 6 ms 8172 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 8172 KB Output is correct
2 Correct 6 ms 8172 KB Output is correct
3 Correct 6 ms 8172 KB Output is correct
4 Incorrect 6 ms 8172 KB Output isn't correct
5 Halted 0 ms 0 KB -