#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 7;
const int INF = 1e9 + 7;
struct Edge{
int v, c;
Edge(int _v, int _c){
v = _v;
c = _c;
}
};
int n, dp[N][3];
vector<Edge> adj[N];
void Dfs(int u, int p){
dp[u][0] = 0;
dp[u][1] = -INF;
dp[u][2] = 0;
for(Edge e : adj[u]){
int v = e.v;
int c = e.c;
if (v == p)
continue;
Dfs(v, u);
int nxtDp[3] = {-INF, -INF, -INF};
nxtDp[0] = max(nxtDp[0], dp[u][0] + dp[v][0]);
nxtDp[0] = max(nxtDp[0], dp[u][0] + dp[v][1] + c);
nxtDp[0] = max(nxtDp[0], dp[u][0] + dp[v][2]);
nxtDp[1] = max(nxtDp[1], dp[u][0] + dp[v][0] + c);
nxtDp[1] = max(nxtDp[1], dp[u][0] + dp[v][2] + c);
nxtDp[1] = max(nxtDp[1], dp[u][1] + dp[v][0]);
nxtDp[1] = max(nxtDp[1], dp[u][1] + dp[v][1] + c);
nxtDp[1] = max(nxtDp[1], dp[u][1] + dp[v][2]);
nxtDp[2] = max(nxtDp[2], dp[u][1] + dp[v][0] + c);
nxtDp[2] = max(nxtDp[2], dp[u][1] + dp[v][2] + c);
nxtDp[2] = max(nxtDp[2], dp[u][2] + dp[v][0]);
nxtDp[2] = max(nxtDp[2], dp[u][2] + dp[v][1] + c);
nxtDp[2] = max(nxtDp[2], dp[u][2] + dp[v][2]);
dp[u][0] = nxtDp[0];
dp[u][1] = nxtDp[1];
dp[u][2] = nxtDp[2];
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n;
for(int i = 1; i < n; i++){
int u, v, c;
cin >> u >> v >> c;
adj[u].push_back(Edge(v, c));
adj[v].push_back(Edge(u, c));
}
Dfs(1, -1);
cout << max(dp[1][0], dp[1][2]);
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
3 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Incorrect |
3 ms |
4940 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
3 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Incorrect |
3 ms |
4940 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
3 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Incorrect |
3 ms |
4940 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
4940 KB |
Output is correct |
2 |
Correct |
3 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Incorrect |
3 ms |
4940 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |