#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
int n;
ll dp[200001][4]; // 00 -> left mask : grow upward/downward, right mask : include free upedge or not
vector<pii> adj[200001];
void dfs(int x, int par, int w) {
ll sum=0;
vector<ll> best[4];
for (auto s : adj[x]) {
if (s.first==par) continue;
dfs(s.first,x,s.second);
sum+=dp[s.first][0];
for (int i=0; i<4; ++i) best[i].push_back(dp[s.first][i]-dp[s.first][0]);
}
for (int i=0; i<4; ++i) sort(best[i].begin(),best[i].end(),greater<ll>());
if (best[0].size()) {
dp[x][0]=max(sum,sum+best[1][0]+w);
dp[x][1]=sum+w;
dp[x][2]=max({sum+best[1][0]+best[3][0],sum+best[2][0],sum+best[3][0]+w});
dp[x][3]=max(sum+best[1][0]+best[3][0],sum+best[2][0])+w;
if (best[0].size()>=2) {
dp[x][2]=max(dp[x][2],sum+best[1][0]+best[1][1]);
dp[x][3]=max(dp[x][3],sum+best[1][0]+best[1][1]+w);
}
} else {
dp[x][0]=0;
dp[x][1]=w;
dp[x][2]=-1e15;
dp[x][3]=-1e15;
}
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n;
for (int i=0; i<n-1; ++i) {
int a,b,w;
cin>>a>>b>>w;
adj[a].push_back(pii(b,w));
adj[b].push_back(pii(a,w));
}
dfs(1,0,0);
cout<<max(dp[1][1],dp[1][3]);
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
4948 KB |
Output is correct |
2 |
Correct |
2 ms |
4948 KB |
Output is correct |
3 |
Correct |
2 ms |
4948 KB |
Output is correct |
4 |
Correct |
3 ms |
4948 KB |
Output is correct |
5 |
Correct |
2 ms |
5036 KB |
Output is correct |
6 |
Correct |
3 ms |
4948 KB |
Output is correct |
7 |
Correct |
3 ms |
4948 KB |
Output is correct |
8 |
Correct |
3 ms |
5028 KB |
Output is correct |
9 |
Correct |
2 ms |
4948 KB |
Output is correct |
10 |
Correct |
3 ms |
4948 KB |
Output is correct |
11 |
Incorrect |
3 ms |
5036 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
4948 KB |
Output is correct |
2 |
Correct |
2 ms |
4948 KB |
Output is correct |
3 |
Correct |
2 ms |
4948 KB |
Output is correct |
4 |
Correct |
3 ms |
4948 KB |
Output is correct |
5 |
Correct |
2 ms |
5036 KB |
Output is correct |
6 |
Correct |
3 ms |
4948 KB |
Output is correct |
7 |
Correct |
3 ms |
4948 KB |
Output is correct |
8 |
Correct |
3 ms |
5028 KB |
Output is correct |
9 |
Correct |
2 ms |
4948 KB |
Output is correct |
10 |
Correct |
3 ms |
4948 KB |
Output is correct |
11 |
Incorrect |
3 ms |
5036 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
4948 KB |
Output is correct |
2 |
Correct |
2 ms |
4948 KB |
Output is correct |
3 |
Correct |
2 ms |
4948 KB |
Output is correct |
4 |
Correct |
3 ms |
4948 KB |
Output is correct |
5 |
Correct |
2 ms |
5036 KB |
Output is correct |
6 |
Correct |
3 ms |
4948 KB |
Output is correct |
7 |
Correct |
3 ms |
4948 KB |
Output is correct |
8 |
Correct |
3 ms |
5028 KB |
Output is correct |
9 |
Correct |
2 ms |
4948 KB |
Output is correct |
10 |
Correct |
3 ms |
4948 KB |
Output is correct |
11 |
Incorrect |
3 ms |
5036 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
4948 KB |
Output is correct |
2 |
Correct |
2 ms |
4948 KB |
Output is correct |
3 |
Correct |
2 ms |
4948 KB |
Output is correct |
4 |
Correct |
3 ms |
4948 KB |
Output is correct |
5 |
Correct |
2 ms |
5036 KB |
Output is correct |
6 |
Correct |
3 ms |
4948 KB |
Output is correct |
7 |
Correct |
3 ms |
4948 KB |
Output is correct |
8 |
Correct |
3 ms |
5028 KB |
Output is correct |
9 |
Correct |
2 ms |
4948 KB |
Output is correct |
10 |
Correct |
3 ms |
4948 KB |
Output is correct |
11 |
Incorrect |
3 ms |
5036 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |