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Submission #697299

# Submission time Handle Problem Language Result Execution time Memory
697299 2023-02-09T07:23:49 Z vjudge1 Beads and wires (APIO14_beads) C++14
100 / 100
 162 ms 36748 KB 
#include<bits/stdc++.h>
#define ll long long
#define lll __int128
#define db double
#define ld long double
#define pii pair<int,int>
#define fi first
#define se second
#define vi vector<int>
using namespace std;
namespace IO
{
	const int SZ=1<<20;
	char gchar()
	{
	    static char buf[SZ];
	    static int i=SZ;
	    if(i==SZ)i=0,fread(buf,1,SZ,stdin);
	    return buf[i++];
	}
	void pchar(char c)
	{
	    static char buf[SZ];
	    static int i=0;
	    if(c)buf[i++]=c;
	    if(!c||i==SZ)fwrite(buf,1,i,stdout),i=0;
	}
	void pstr(string s,char end='\n')
	{
		for(char c:s)pchar(c);
		pchar(end);
	}
	template<typename T>void read(T &u)
	{
	    u=0;int f=1;
	    static char c;
	    while((c=gchar())>'9'||c<'0')if(c=='-')f=-1;
	    u=c-'0';
	    while((c=gchar())>='0'&&c<='9')
			u=(u<<1)+(u<<3)+(c^48);
		u*=f;
	}
	template<typename T,typename ...Args>void read(T &u,Args&...args){read(u),read(args...);}
	template<typename T>void i_write(T u)
	{
	    if(u>9)i_write(u/10);
	    pchar(u%10+'0');
	}
	template<typename T>void write(T u,char end='\n')
	{
	    if(u<0)pchar('-'),u=-u;
	    if(u>9)i_write(u/10);
	    pchar(u%10+'0');
	    pchar(end);
	}
}
using IO::read;
using IO::write;
const int N=2e5+10;
const ll inf=1e18;
int n;
vector<pii>e[N];
int v1[N],v2[N];
ll mx1[N],mx2[N],vg[N],f[N][2],g[N][2],h[N][2];
void dfs1(int u,int fa)
{
	mx1[u]=mx2[u]=-inf,v1[u]=v2[u]=0;
	for(auto it:e[u])
	{
		int v=it.fi,w=it.se;
		if(v==fa)continue;
		vg[v]=w,dfs1(v,u),f[u][0]+=max(f[v][0],f[v][1]+w);
		ll val=f[v][0]+w-max(f[v][0],f[v][1]+w);
		if(mx1[u]<val)v2[u]=v1[u],mx2[u]=mx1[u],v1[u]=v,mx1[u]=val;
		else if(mx2[u]<val)v2[u]=v,mx2[u]=val;
	}
	f[u][1]=f[u][0]+mx1[u];
}
void dfs2(int u,int fa)
{
	for(auto it:e[u])
	{
		int v=it.fi,w=it.se;
		if(v==fa)continue;
		if(v1[u]==v)swap(mx1[u],mx2[u]),swap(v1[u],v2[u]);
		h[u][0]=g[u][0]-max(f[v][0],f[v][1]+w),h[u][1]=h[u][0]+mx1[u];
		if(u>1)h[u][1]=max(h[u][1],h[u][0]+h[fa][0]+vg[u]-max(h[fa][0],h[fa][1]+vg[u]));
		g[v][0]=f[v][0]+max(h[u][0],h[u][1]+w);
		if(mx1[u]<mx2[u])swap(mx1[u],mx2[u]),swap(v1[u],v2[u]);
		dfs2(v,u);
	}
}
int main()
{
	read(n);
	for(int i=1,x,y,z;i<n;i++)
		read(x,y,z),e[x].push_back({y,z}),e[y].push_back({x,z});
	dfs1(1,0),g[1][0]=f[1][0],dfs2(1,0);
	ll ans=0;
	for(int i=1;i<=n;i++)ans=max(ans,g[i][0]);
	printf("%lld",ans);
	return 0;
}

Compilation message

beads.cpp: In function 'char IO::gchar()':
beads.cpp:18:24: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |      if(i==SZ)i=0,fread(buf,1,SZ,stdin);
      |                   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5068 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 5020 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 5012 KB Output is correct
8 Correct 3 ms 5012 KB Output is correct
9 Correct 3 ms 5020 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 5016 KB Output is correct
12 Correct 3 ms 5016 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5068 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 5020 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 5012 KB Output is correct
8 Correct 3 ms 5012 KB Output is correct
9 Correct 3 ms 5020 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 5016 KB Output is correct
12 Correct 3 ms 5016 KB Output is correct
13 Correct 2 ms 5016 KB Output is correct
14 Correct 3 ms 5016 KB Output is correct
15 Correct 3 ms 5076 KB Output is correct
16 Correct 3 ms 5020 KB Output is correct
17 Correct 3 ms 5076 KB Output is correct
18 Correct 3 ms 5076 KB Output is correct
19 Correct 3 ms 5076 KB Output is correct
20 Correct 3 ms 5076 KB Output is correct
21 Correct 3 ms 5088 KB Output is correct
22 Correct 3 ms 5012 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5068 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 5020 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 5012 KB Output is correct
8 Correct 3 ms 5012 KB Output is correct
9 Correct 3 ms 5020 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 5016 KB Output is correct
12 Correct 3 ms 5016 KB Output is correct
13 Correct 2 ms 5016 KB Output is correct
14 Correct 3 ms 5016 KB Output is correct
15 Correct 3 ms 5076 KB Output is correct
16 Correct 3 ms 5020 KB Output is correct
17 Correct 3 ms 5076 KB Output is correct
18 Correct 3 ms 5076 KB Output is correct
19 Correct 3 ms 5076 KB Output is correct
20 Correct 3 ms 5076 KB Output is correct
21 Correct 3 ms 5088 KB Output is correct
22 Correct 3 ms 5012 KB Output is correct
23 Correct 4 ms 5720 KB Output is correct
24 Correct 4 ms 5720 KB Output is correct
25 Correct 5 ms 5720 KB Output is correct
26 Correct 6 ms 6448 KB Output is correct
27 Correct 6 ms 6484 KB Output is correct
28 Correct 5 ms 6568 KB Output is correct
29 Correct 5 ms 6356 KB Output is correct
30 Correct 5 ms 6440 KB Output is correct
31 Correct 6 ms 6824 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5068 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 5020 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 5012 KB Output is correct
8 Correct 3 ms 5012 KB Output is correct
9 Correct 3 ms 5020 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 5016 KB Output is correct
12 Correct 3 ms 5016 KB Output is correct
13 Correct 2 ms 5016 KB Output is correct
14 Correct 3 ms 5016 KB Output is correct
15 Correct 3 ms 5076 KB Output is correct
16 Correct 3 ms 5020 KB Output is correct
17 Correct 3 ms 5076 KB Output is correct
18 Correct 3 ms 5076 KB Output is correct
19 Correct 3 ms 5076 KB Output is correct
20 Correct 3 ms 5076 KB Output is correct
21 Correct 3 ms 5088 KB Output is correct
22 Correct 3 ms 5012 KB Output is correct
23 Correct 4 ms 5720 KB Output is correct
24 Correct 4 ms 5720 KB Output is correct
25 Correct 5 ms 5720 KB Output is correct
26 Correct 6 ms 6448 KB Output is correct
27 Correct 6 ms 6484 KB Output is correct
28 Correct 5 ms 6568 KB Output is correct
29 Correct 5 ms 6356 KB Output is correct
30 Correct 5 ms 6440 KB Output is correct
31 Correct 6 ms 6824 KB Output is correct
32 Correct 22 ms 12376 KB Output is correct
33 Correct 20 ms 12244 KB Output is correct
34 Correct 21 ms 12260 KB Output is correct
35 Correct 162 ms 31564 KB Output is correct
36 Correct 141 ms 31444 KB Output is correct
37 Correct 144 ms 31432 KB Output is correct
38 Correct 83 ms 31856 KB Output is correct
39 Correct 81 ms 28812 KB Output is correct
40 Correct 86 ms 31748 KB Output is correct
41 Correct 137 ms 36748 KB Output is correct