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Submission #110938

# Submission time Handle Problem Language Result Execution time Memory
110938 2019-05-13T09:03:26 Z zscoder Beads and wires (APIO14_beads) C++17
100 / 100
 363 ms 26224 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("unroll-loops,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;
using namespace __gnu_pbds;
 
#define fi first
#define se second
#define mp make_pair
#define pb push_back
 
typedef long long ll;
typedef pair<int,int> ii;
typedef vector<ll> vi;
typedef unsigned long long ull;
typedef long double ld; 
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> pbds;

const int N = 333333;
vector<ii> adj[N];
int dp[N][2];
const int INF = int(1e9);
int dp2[N][2];

void dfs(int u, int p)
{
	vi pre(2,-INF); pre[0]=0;
	dp[u][0]=dp[u][1]=-INF;
	for(ii X:adj[u])
	{
		int v=X.fi; int w=X.se;
		if(v==p) continue;
		dfs(v,u);
		vi nw(2,-INF);
		nw[0]=max(nw[0],pre[0]+dp[v][0]);
		nw[1]=max(nw[1],pre[1]+dp[v][0]);
		
		nw[0]=max(nw[0],pre[0]+w+dp[v][1]);
		nw[1]=max(nw[1],pre[0]+w+dp[v][0]);
		nw[1]=max(nw[1],pre[1]+w+dp[v][1]);
		pre=nw;
	}
	dp[u][0]=pre[0]; dp[u][1]=pre[1];
	//cerr<<u<<' '<<dp[u][0]<<' '<<dp[u][1]<<'\n';
}

void dfs2(int u, int p)
{
	int sum=dp2[u][0];
	vector<ii> vec;
	vec.pb({dp2[u][1]-dp2[u][0],u});
	for(ii X:adj[u])
	{
		int v=X.fi; int w=X.se;
		if(v==p) continue;
		sum+=max(dp[v][0],dp[v][1]+w);
		int nwval = dp[v][0]+w;
		vec.pb({nwval-max(dp[v][0],dp[v][1]+w),v});
	}
	sort(vec.rbegin(),vec.rend());
	for(ii X:adj[u])
	{
		int v=X.fi; int w=X.se;
		if(v==p) continue;
		//compute dp2[v][0], dp2[v][1]
		dp2[v][1]=-INF;
		sum-=max(dp[v][0],dp[v][1]+w);
		if(w+sum>=0) dp2[v][1]=w+sum;
		dp2[v][0]=sum;
		int largest=vec[0].fi;
		if(vec[0].se==v)
		{
			if(vec.size()<=1) largest=-INF;
			else largest=vec[1].fi;
		}
		dp2[v][0]=max(dp2[v][0],w+sum+largest);
		sum+=max(dp[v][0],dp[v][1]+w);
		dfs2(v,u);		
	}
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0); 
	int n; cin>>n;
	for(int i=0;i<n-1;i++)
	{
		int u,v; cin>>u>>v; u--; v--;
		int w; cin>>w;
		adj[u].pb({v,w});
		adj[v].pb({u,w});
	}
	int ans=0;
	dfs(0,-1);
	dp2[0][0]=0; dp2[0][1]=-INF;
	dfs2(0,-1);
	for(int i=0;i<n;i++)
	{
		ans=max(ans,dp[i][0]+dp2[i][0]);
	}
	cout<<ans<<'\n';
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 8192 KB Output is correct
2 Correct 9 ms 8192 KB Output is correct
3 Correct 9 ms 8192 KB Output is correct
4 Correct 9 ms 8192 KB Output is correct
5 Correct 8 ms 8192 KB Output is correct
6 Correct 8 ms 8192 KB Output is correct
7 Correct 9 ms 8192 KB Output is correct
8 Correct 9 ms 8192 KB Output is correct
9 Correct 9 ms 8192 KB Output is correct
10 Correct 9 ms 8192 KB Output is correct
11 Correct 8 ms 8192 KB Output is correct
12 Correct 8 ms 8192 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 8192 KB Output is correct
2 Correct 9 ms 8192 KB Output is correct
3 Correct 9 ms 8192 KB Output is correct
4 Correct 9 ms 8192 KB Output is correct
5 Correct 8 ms 8192 KB Output is correct
6 Correct 8 ms 8192 KB Output is correct
7 Correct 9 ms 8192 KB Output is correct
8 Correct 9 ms 8192 KB Output is correct
9 Correct 9 ms 8192 KB Output is correct
10 Correct 9 ms 8192 KB Output is correct
11 Correct 8 ms 8192 KB Output is correct
12 Correct 8 ms 8192 KB Output is correct
13 Correct 8 ms 8192 KB Output is correct
14 Correct 8 ms 8192 KB Output is correct
15 Correct 8 ms 8164 KB Output is correct
16 Correct 8 ms 8192 KB Output is correct
17 Correct 8 ms 8192 KB Output is correct
18 Correct 8 ms 8192 KB Output is correct
19 Correct 8 ms 8192 KB Output is correct
20 Correct 8 ms 8192 KB Output is correct
21 Correct 8 ms 8192 KB Output is correct
22 Correct 8 ms 8192 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 8192 KB Output is correct
2 Correct 9 ms 8192 KB Output is correct
3 Correct 9 ms 8192 KB Output is correct
4 Correct 9 ms 8192 KB Output is correct
5 Correct 8 ms 8192 KB Output is correct
6 Correct 8 ms 8192 KB Output is correct
7 Correct 9 ms 8192 KB Output is correct
8 Correct 9 ms 8192 KB Output is correct
9 Correct 9 ms 8192 KB Output is correct
10 Correct 9 ms 8192 KB Output is correct
11 Correct 8 ms 8192 KB Output is correct
12 Correct 8 ms 8192 KB Output is correct
13 Correct 8 ms 8192 KB Output is correct
14 Correct 8 ms 8192 KB Output is correct
15 Correct 8 ms 8164 KB Output is correct
16 Correct 8 ms 8192 KB Output is correct
17 Correct 8 ms 8192 KB Output is correct
18 Correct 8 ms 8192 KB Output is correct
19 Correct 8 ms 8192 KB Output is correct
20 Correct 8 ms 8192 KB Output is correct
21 Correct 8 ms 8192 KB Output is correct
22 Correct 8 ms 8192 KB Output is correct
23 Correct 12 ms 8448 KB Output is correct
24 Correct 12 ms 8448 KB Output is correct
25 Correct 12 ms 8448 KB Output is correct
26 Correct 16 ms 8704 KB Output is correct
27 Correct 16 ms 8704 KB Output is correct
28 Correct 17 ms 8960 KB Output is correct
29 Correct 15 ms 8832 KB Output is correct
30 Correct 15 ms 8832 KB Output is correct
31 Correct 17 ms 9472 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 8192 KB Output is correct
2 Correct 9 ms 8192 KB Output is correct
3 Correct 9 ms 8192 KB Output is correct
4 Correct 9 ms 8192 KB Output is correct
5 Correct 8 ms 8192 KB Output is correct
6 Correct 8 ms 8192 KB Output is correct
7 Correct 9 ms 8192 KB Output is correct
8 Correct 9 ms 8192 KB Output is correct
9 Correct 9 ms 8192 KB Output is correct
10 Correct 9 ms 8192 KB Output is correct
11 Correct 8 ms 8192 KB Output is correct
12 Correct 8 ms 8192 KB Output is correct
13 Correct 8 ms 8192 KB Output is correct
14 Correct 8 ms 8192 KB Output is correct
15 Correct 8 ms 8164 KB Output is correct
16 Correct 8 ms 8192 KB Output is correct
17 Correct 8 ms 8192 KB Output is correct
18 Correct 8 ms 8192 KB Output is correct
19 Correct 8 ms 8192 KB Output is correct
20 Correct 8 ms 8192 KB Output is correct
21 Correct 8 ms 8192 KB Output is correct
22 Correct 8 ms 8192 KB Output is correct
23 Correct 12 ms 8448 KB Output is correct
24 Correct 12 ms 8448 KB Output is correct
25 Correct 12 ms 8448 KB Output is correct
26 Correct 16 ms 8704 KB Output is correct
27 Correct 16 ms 8704 KB Output is correct
28 Correct 17 ms 8960 KB Output is correct
29 Correct 15 ms 8832 KB Output is correct
30 Correct 15 ms 8832 KB Output is correct
31 Correct 17 ms 9472 KB Output is correct
32 Correct 69 ms 10812 KB Output is correct
33 Correct 79 ms 10872 KB Output is correct
34 Correct 57 ms 10872 KB Output is correct
35 Correct 332 ms 18936 KB Output is correct
36 Correct 347 ms 18904 KB Output is correct
37 Correct 357 ms 18848 KB Output is correct
38 Correct 272 ms 20712 KB Output is correct
39 Correct 286 ms 21464 KB Output is correct
40 Correct 288 ms 20928 KB Output is correct
41 Correct 363 ms 26224 KB Output is correct