oj.uz

Submission #26421

# Submission time Handle Problem Language Result Execution time Memory
26421 2017-06-30T04:56:20 Z zscoder Beads and wires (APIO14_beads) C++14
100 / 100
 273 ms 27748 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key

typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef long double ld; 
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
typedef set<int>::iterator sit;
typedef map<int,int>::iterator mit;
typedef vector<int>::iterator vit;

vector<ii> adj[200001];
ll dp[200001][2];
ll dp2[200001][2];
const ll INF = ll(1e15);

void dfs(int u, int p)
{
	int childcnt=0;
	ll maxi=-INF;
	dp[u][1]=-INF;
	for(int i=0;i<adj[u].size();i++)
	{
		int v=adj[u][i].fi; int w=adj[u][i].se;
		if(v==p) continue;
		childcnt++;
		dfs(v,u);
		dp[u][0]+=max(dp[v][0],dp[v][1]+w);
		maxi=max(maxi,-max(dp[v][0],dp[v][1]+w)+w+dp[v][0]);
	}
	if(childcnt>0) 
	{
		dp[u][1]=maxi+dp[u][0];
	}
	//cerr<<u+1<<' '<<b1<<' '<<b2<<'\n';
	//cerr<<u+1<<' '<<dp[u][0]<<' '<<dp[u][1]<<'\n';
}
ll par[200001];
void dfs2(int u, int p)
{
	//cerr<<u+1<<' '<<dp[u][0]<<' '<<dp[u][1]<<'\n';
	ll maxi1 = -INF; ll maxi2 = -INF;
	ll idx1 = -1; ll idx2 = -1;
	for(int i=0;i<adj[u].size();i++)
	{
		int v=adj[u][i].fi; int w=adj[u][i].se;
		par[v]=w;
		if(v==p) continue;
		ll val = -max(dp[v][0],dp[v][1]+w)+w+dp[v][0];
		if(val>maxi1)
		{
			maxi2=maxi1;
			idx2=idx1;
			maxi1=val;
			idx1=i;
		}
		else if(val>maxi2)
		{
			maxi2=val;
			idx2=i;
		}
	}
	if(p!=-1)
	{
		ll val = -max(dp2[u][0],dp2[u][1]+par[u])+par[u]+dp2[u][0];
		if(val>maxi1)
		{
			maxi2=maxi1;
			idx2=idx1;
			idx1=-2;
			maxi1=val;
		}
		else if(val>maxi2)
		{
			maxi2=val;
		}
	}
	for(int i=0;i<adj[u].size();i++)
	{
		int v=adj[u][i].fi; int w=adj[u][i].se;
		if(v==p) continue;
		ll dpu0 = dp[u][0] - max(dp[v][0],dp[v][1]+w);
		ll dpu1 = dpu0 + maxi1;
		if(idx1==i)
		{
			dpu1=dpu0+maxi2;
		}
		ll tmp = dp[v][0];
		//cerr<<u+1<<' '<<v+1<<' '<<dpu0<<' '<<dpu1<<' '<<maxi1<<' '<<maxi2<<'\n';
		dp[v][0] = tmp+max(dpu0,dpu1+w);
		ll maxi = dp[v][1]-tmp;
		maxi=max(maxi,-max(dpu0,dpu1+w)+w+dpu0);
		dp[v][1] = dp[v][0] + maxi;
		dp2[v][0]=dpu0;
		dp2[v][1]=dpu1;
	}
	for(int i=0;i<adj[u].size();i++)
	{
		int v=adj[u][i].fi; int w=adj[u][i].se;
		if(v==p) continue;
		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;
		int w; cin>>w;
		u--; v--;
		adj[u].pb(mp(v,w));
		adj[v].pb(mp(u,w));
	}
	ll ans = 0;
	dfs(0,-1);
	dfs2(0,-1);
	for(int i=0;i<n;i++) ans=max(ans,dp[i][0]);
	cout<<ans<<'\n';
}

Compilation message

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:34:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<adj[u].size();i++)
              ~^~~~~~~~~~~~~~
beads.cpp: In function 'void dfs2(int, int)':
beads.cpp:56:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<adj[u].size();i++)
              ~^~~~~~~~~~~~~~
beads.cpp:90:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<adj[u].size();i++)
              ~^~~~~~~~~~~~~~
beads.cpp:109:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<adj[u].size();i++)
              ~^~~~~~~~~~~~~~
beads.cpp:111:27: warning: unused variable 'w' [-Wunused-variable]
   int v=adj[u][i].fi; int w=adj[u][i].se;
                           ^
beads.cpp:55:19: warning: variable 'idx2' set but not used [-Wunused-but-set-variable]
  ll idx1 = -1; ll idx2 = -1;
                   ^~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 5 ms 5120 KB Output is correct
4 Correct 6 ms 5120 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 5 ms 5120 KB Output is correct
12 Correct 6 ms 5092 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 5 ms 5120 KB Output is correct
4 Correct 6 ms 5120 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 5 ms 5120 KB Output is correct
12 Correct 6 ms 5092 KB Output is correct
13 Correct 7 ms 5248 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 7 ms 5248 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 5 ms 5120 KB Output is correct
4 Correct 6 ms 5120 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 5 ms 5120 KB Output is correct
12 Correct 6 ms 5092 KB Output is correct
13 Correct 7 ms 5248 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 7 ms 5248 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct
23 Correct 9 ms 5504 KB Output is correct
24 Correct 9 ms 5504 KB Output is correct
25 Correct 8 ms 5504 KB Output is correct
26 Correct 12 ms 6016 KB Output is correct
27 Correct 12 ms 6016 KB Output is correct
28 Correct 10 ms 6012 KB Output is correct
29 Correct 11 ms 5888 KB Output is correct
30 Correct 11 ms 6016 KB Output is correct
31 Correct 11 ms 6400 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 5 ms 5120 KB Output is correct
4 Correct 6 ms 5120 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 5 ms 5120 KB Output is correct
12 Correct 6 ms 5092 KB Output is correct
13 Correct 7 ms 5248 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 7 ms 5248 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct
23 Correct 9 ms 5504 KB Output is correct
24 Correct 9 ms 5504 KB Output is correct
25 Correct 8 ms 5504 KB Output is correct
26 Correct 12 ms 6016 KB Output is correct
27 Correct 12 ms 6016 KB Output is correct
28 Correct 10 ms 6012 KB Output is correct
29 Correct 11 ms 5888 KB Output is correct
30 Correct 11 ms 6016 KB Output is correct
31 Correct 11 ms 6400 KB Output is correct
32 Correct 38 ms 9664 KB Output is correct
33 Correct 36 ms 9600 KB Output is correct
34 Correct 41 ms 9592 KB Output is correct
35 Correct 260 ms 23160 KB Output is correct
36 Correct 273 ms 23156 KB Output is correct
37 Correct 268 ms 23288 KB Output is correct
38 Correct 210 ms 22364 KB Output is correct
39 Correct 195 ms 22356 KB Output is correct
40 Correct 181 ms 22356 KB Output is correct
41 Correct 240 ms 27748 KB Output is correct