#include<bits/stdc++.h>
using namespace std;
const int MAXN=212345,INF=1123456789;
vector<int> grafo[MAXN],peso[MAXN];
int dp[MAXN][5],marc[MAXN];
void dfs(int v,int p)
{
marc[v]=1;
if(v!=0 && grafo[v].size()==1)
{
dp[v][0]=0;dp[v][1]=p;dp[v][2]=0;
return;
}
int d1=-INF,d2=-INF,tot=0;
for(int i=0;i<grafo[v].size();i++)
{
int viz=grafo[v][i],ps=peso[v][i];
if(marc[viz]==1)continue;
dfs(viz,ps);
if(dp[viz][1]-max(dp[viz][0],dp[viz][2])>d1)d1=dp[viz][1]-max(dp[viz][0],dp[viz][2]);
if(d1>d2)swap(d1,d2);
tot+=max(dp[viz][0],dp[viz][2]);
}
dp[v][0]=max(tot+d1+d2,tot);
dp[v][2]=tot+d2+p;
dp[v][1]=max(tot+d1+d2+p,tot+p);
}
int main()
{
int n;
scanf("%d",&n);
for(int i=0;i<n-1;i++)
{
int a,b,p;
scanf("%d %d %d",&a,&b,&p);a--;b--;
grafo[a].push_back(b);grafo[b].push_back(a);
peso[a].push_back(p);peso[b].push_back(p);
}
int resp=0;
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
dp[i][0]=0;dp[i][1]=0;dp[i][2]=0;
marc[j]=0;
}
dfs(i,0);
resp=max(dp[i][0],resp);
}
printf("%d\n",resp);
/*for(int i=0;i<n;i++)
{
printf("%d %d %d %d\n",i,dp[i][0],dp[i][1],dp[i][2]);
}*/
return 0;
}
Compilation message
beads.cpp: In function 'void dfs(int, int)':
beads.cpp:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<grafo[v].size();i++)
~^~~~~~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&n);
~~~~~^~~~~~~~~
beads.cpp:35:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d %d",&a,&b,&p);a--;b--;
~~~~~^~~~~~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
10360 KB |
Output is correct |
2 |
Correct |
10 ms |
10364 KB |
Output is correct |
3 |
Incorrect |
10 ms |
10344 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
10360 KB |
Output is correct |
2 |
Correct |
10 ms |
10364 KB |
Output is correct |
3 |
Incorrect |
10 ms |
10344 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
10360 KB |
Output is correct |
2 |
Correct |
10 ms |
10364 KB |
Output is correct |
3 |
Incorrect |
10 ms |
10344 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
10360 KB |
Output is correct |
2 |
Correct |
10 ms |
10364 KB |
Output is correct |
3 |
Incorrect |
10 ms |
10344 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |