#include<bits/stdc++.h>
using namespace std;
template <typename T> inline void read(T &x)
{
x=0;T f=1;char c=getchar();
for(;!isdigit(c);c=getchar()) if(c=='-')f=-1;
for(;isdigit(c);c=getchar()) x=(x<<1)+(x<<3)+(c^48);
x*=f;
}
template <typename T,typename ...Args>void read(T &x,Args&...args){read(x),read(args...);}
template <typename T> void print(T x)
{
if(x<0) x=-x,putchar('-');
if(x>9) print(x/10);
putchar(x%10+48);
}
template <typename T> void print(T x,char c){print(x); putchar(c);}
template<typename T>inline void output(T x){print(x,' ');}
template<typename T,typename ...Arg>inline void output(T x,Arg ...arg){output(x);output(arg...);}
const int N=200007; const long long inf=0x3f3f3f3f3f3f3f3f;
int n,cnt,h[N],vfa[N],v[2][N];
long long ans,f[N][2],g[N][2],dp[N][2],mx[2][N];
struct edge{int to,nxt,w;}mp[N<<1];
void add(int x,int y,int z)
{
cnt++;
mp[cnt].nxt=h[x];
mp[cnt].to=y;
mp[cnt].w=z;
h[x]=cnt;
}
void solve1(int x,int fa)
{
mx[0][x]=mx[1][x]=-inf;
v[0][x]=v[1][x]=0;
for(int i=h[x];i;i=mp[i].nxt)
{
int y=mp[i].to,w=mp[i].w;
if(y==fa) continue;
vfa[y]=w; solve1(y,x);
f[x][0]+=max(f[y][0],f[y][1]+w);
long long val=f[y][0]+w-max(f[y][0],f[y][1]+w);
if(mx[0][x]<val)
v[1][x]=v[0][x],
mx[1][x]=mx[0][x],
v[0][x]=y,mx[0][x]=val;
else if(mx[1][x]<val)
v[1][x]=y,mx[1][x]=val;
}
f[x][1]=f[x][0]+mx[0][x];
}
void solve2(int x,int fa)
{
for(int i=h[x];i;i=mp[i].nxt)
{
int y=mp[i].to,w=mp[i].w;
if(y==fa) continue;
if(v[0][x]==y)
swap(mx[0][x],mx[1][x]),
swap(v[0][x],v[1][x]);
dp[x][0]=g[x][0]-max(f[y][0],f[y][1]+w);
dp[x][1]=dp[x][0]+mx[0][x];
if(x>1)
dp[x][1]=max(dp[x][1],dp[x][0]+dp[fa][0]+vfa[x]-max(dp[fa][0],dp[fa][1]+vfa[x]));
g[y][0]=f[y][0]+max(dp[x][0],dp[x][1]+w);
if(mx[0][x]<mx[1][x])
swap(mx[0][x],mx[1][x]),
swap(v[0][x],v[1][x]);
solve2(y,x);
}
}
int main()
{
read(n);
for(int i=1,x,y,z;i<n;i++)
read(x,y,z),add(x,y,z),add(y,x,z);
solve1(1,0);
g[1][0]=f[1][0];
solve2(1,0);
for(int i=1;i<=n;i++)
ans=max(ans,g[i][0]);
print(ans,'\n');
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
1 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
0 ms |
312 KB |
Output is correct |
9 |
Correct |
0 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
1 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
0 ms |
312 KB |
Output is correct |
9 |
Correct |
0 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
1 ms |
340 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
1 ms |
340 KB |
Output is correct |
15 |
Correct |
1 ms |
312 KB |
Output is correct |
16 |
Correct |
1 ms |
308 KB |
Output is correct |
17 |
Correct |
1 ms |
340 KB |
Output is correct |
18 |
Correct |
1 ms |
308 KB |
Output is correct |
19 |
Correct |
1 ms |
312 KB |
Output is correct |
20 |
Correct |
1 ms |
340 KB |
Output is correct |
21 |
Correct |
1 ms |
340 KB |
Output is correct |
22 |
Correct |
1 ms |
340 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
1 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
0 ms |
312 KB |
Output is correct |
9 |
Correct |
0 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
1 ms |
340 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
1 ms |
340 KB |
Output is correct |
15 |
Correct |
1 ms |
312 KB |
Output is correct |
16 |
Correct |
1 ms |
308 KB |
Output is correct |
17 |
Correct |
1 ms |
340 KB |
Output is correct |
18 |
Correct |
1 ms |
308 KB |
Output is correct |
19 |
Correct |
1 ms |
312 KB |
Output is correct |
20 |
Correct |
1 ms |
340 KB |
Output is correct |
21 |
Correct |
1 ms |
340 KB |
Output is correct |
22 |
Correct |
1 ms |
340 KB |
Output is correct |
23 |
Correct |
1 ms |
852 KB |
Output is correct |
24 |
Correct |
2 ms |
928 KB |
Output is correct |
25 |
Correct |
2 ms |
852 KB |
Output is correct |
26 |
Correct |
3 ms |
1492 KB |
Output is correct |
27 |
Correct |
2 ms |
1472 KB |
Output is correct |
28 |
Correct |
3 ms |
1492 KB |
Output is correct |
29 |
Correct |
2 ms |
1364 KB |
Output is correct |
30 |
Correct |
2 ms |
1492 KB |
Output is correct |
31 |
Correct |
3 ms |
1824 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
340 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
1 ms |
340 KB |
Output is correct |
6 |
Correct |
1 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
0 ms |
312 KB |
Output is correct |
9 |
Correct |
0 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
1 ms |
340 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
1 ms |
340 KB |
Output is correct |
15 |
Correct |
1 ms |
312 KB |
Output is correct |
16 |
Correct |
1 ms |
308 KB |
Output is correct |
17 |
Correct |
1 ms |
340 KB |
Output is correct |
18 |
Correct |
1 ms |
308 KB |
Output is correct |
19 |
Correct |
1 ms |
312 KB |
Output is correct |
20 |
Correct |
1 ms |
340 KB |
Output is correct |
21 |
Correct |
1 ms |
340 KB |
Output is correct |
22 |
Correct |
1 ms |
340 KB |
Output is correct |
23 |
Correct |
1 ms |
852 KB |
Output is correct |
24 |
Correct |
2 ms |
928 KB |
Output is correct |
25 |
Correct |
2 ms |
852 KB |
Output is correct |
26 |
Correct |
3 ms |
1492 KB |
Output is correct |
27 |
Correct |
2 ms |
1472 KB |
Output is correct |
28 |
Correct |
3 ms |
1492 KB |
Output is correct |
29 |
Correct |
2 ms |
1364 KB |
Output is correct |
30 |
Correct |
2 ms |
1492 KB |
Output is correct |
31 |
Correct |
3 ms |
1824 KB |
Output is correct |
32 |
Correct |
11 ms |
6172 KB |
Output is correct |
33 |
Correct |
12 ms |
6080 KB |
Output is correct |
34 |
Correct |
12 ms |
6164 KB |
Output is correct |
35 |
Correct |
80 ms |
24088 KB |
Output is correct |
36 |
Correct |
82 ms |
24124 KB |
Output is correct |
37 |
Correct |
84 ms |
24012 KB |
Output is correct |
38 |
Correct |
65 ms |
24144 KB |
Output is correct |
39 |
Correct |
50 ms |
21016 KB |
Output is correct |
40 |
Correct |
58 ms |
24228 KB |
Output is correct |
41 |
Correct |
84 ms |
28404 KB |
Output is correct |