#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <random>
#include <iomanip>
#include <cassert>
#include <complex>
#include <functional>
using namespace std;
typedef long long ll;
const int N = 2e5 + 7;
vector <pair <int, int>> g[N];
int dp[N][2];
void dfs(int u, int p, int wp) {
int sum = 0;
vector <int> vals;
for (auto [v, w] : g[u]) {
if (v != p) {
dfs(v, u, w);
sum += dp[v][1];
vals.push_back(dp[v][0] + w - dp[v][1]);
}
}
dp[u][0] = sum;
sort(vals.rbegin(), vals.rend());
if (vals.size() >= 2) {
dp[u][0] = max(dp[u][0], sum + vals[0] + vals[1]);
}
if (p != -1 && vals.size() >= 1) {
dp[u][1] = sum + vals[0] + wp;
}
dp[u][1] = max(dp[u][1], dp[u][0]);
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
int n;
cin >> n;
for (int i = 0; i + 1 < n; ++i) {
int u, v, w;
cin >> u >> v >> w;
--u, --v;
g[u].push_back({v, w});
g[v].push_back({u, w});
}
dfs(0, -1, 0);
cout << dp[0][1] << '\n';
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
4984 KB |
Output is correct |
4 |
Correct |
6 ms |
5112 KB |
Output is correct |
5 |
Correct |
6 ms |
5112 KB |
Output is correct |
6 |
Incorrect |
6 ms |
5112 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
4984 KB |
Output is correct |
4 |
Correct |
6 ms |
5112 KB |
Output is correct |
5 |
Correct |
6 ms |
5112 KB |
Output is correct |
6 |
Incorrect |
6 ms |
5112 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
4984 KB |
Output is correct |
4 |
Correct |
6 ms |
5112 KB |
Output is correct |
5 |
Correct |
6 ms |
5112 KB |
Output is correct |
6 |
Incorrect |
6 ms |
5112 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
4984 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
4984 KB |
Output is correct |
4 |
Correct |
6 ms |
5112 KB |
Output is correct |
5 |
Correct |
6 ms |
5112 KB |
Output is correct |
6 |
Incorrect |
6 ms |
5112 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |