#include <bits/stdc++.h>
using namespace std;
const int INF = 2e9 + 10;
int main()
{
cin.tie(0)->sync_with_stdio(0);
int n;
cin >> n;
vector<vector<pair<int, int>>> g(n);
for (int i = 0; i < n - 1; i++)
{
int u, v, w;
cin >> u >> v >> w;
u--, v--;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
}
vector<bool> vis(n);
vector<vector<int>> dp(n, vector<int>(4, -INF));
function<void(int, int)> dfs = [&](int u, int W)
{
vis[u] = true;
dp[u][0] = dp[u][2] = 0;
vector<int> res;
for (auto &[v, w] : g[u])
{
if (!vis[v])
{
dfs(v, w);
dp[u][0] += max(dp[v][0], dp[v][1]);
res.push_back(dp[v][0] + w - max(dp[v][0], dp[v][1]));
}
}
sort(begin(res), end(res), greater<>());
if (res.size() >= 1)
{
dp[u][1] = dp[u][0] + W + res[0];
for (auto &[v, w] : g[u])
{
if (!vis[v])
{
dp[u][2] = max(dp[u][2], max(dp[v][2], dp[v][3]) - max(dp[v][0], dp[v][1]) + dp[u][0]);
dp[u][3] = max(dp[u][3], dp[v][2] + w + W - max(dp[v][0], dp[v][1]) + dp[u][0]);
}
}
}
if (res.size() >= 2)
{
for (auto &[v, w] : g[u])
{
if (!vis[v])
{
int x = dp[v][0] + w - max(dp[v][0], dp[v][1]) == res[0] ? res[1] : res[0];
dp[u][2] = max(dp[u][2], dp[u][0] + dp[v][2] + w - max(dp[v][0], dp[v][1]) + x);
}
}
}
dp[u][2] = max(dp[u][2], dp[u][0]);
dp[u][3] = max(dp[u][3], dp[u][1]);
vis[u] = false;
};
dfs(0, -INF);
int ans = max(dp[0][2], dp[0][3]);
cout << ans << '\n';
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
13 |
Correct |
0 ms |
344 KB |
Output is correct |
14 |
Correct |
0 ms |
348 KB |
Output is correct |
15 |
Correct |
0 ms |
348 KB |
Output is correct |
16 |
Correct |
0 ms |
348 KB |
Output is correct |
17 |
Correct |
0 ms |
348 KB |
Output is correct |
18 |
Correct |
0 ms |
348 KB |
Output is correct |
19 |
Correct |
0 ms |
348 KB |
Output is correct |
20 |
Correct |
0 ms |
348 KB |
Output is correct |
21 |
Correct |
0 ms |
348 KB |
Output is correct |
22 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
13 |
Correct |
0 ms |
344 KB |
Output is correct |
14 |
Correct |
0 ms |
348 KB |
Output is correct |
15 |
Correct |
0 ms |
348 KB |
Output is correct |
16 |
Correct |
0 ms |
348 KB |
Output is correct |
17 |
Correct |
0 ms |
348 KB |
Output is correct |
18 |
Correct |
0 ms |
348 KB |
Output is correct |
19 |
Correct |
0 ms |
348 KB |
Output is correct |
20 |
Correct |
0 ms |
348 KB |
Output is correct |
21 |
Correct |
0 ms |
348 KB |
Output is correct |
22 |
Correct |
0 ms |
348 KB |
Output is correct |
23 |
Correct |
2 ms |
860 KB |
Output is correct |
24 |
Correct |
2 ms |
860 KB |
Output is correct |
25 |
Correct |
2 ms |
856 KB |
Output is correct |
26 |
Correct |
3 ms |
1628 KB |
Output is correct |
27 |
Correct |
3 ms |
1628 KB |
Output is correct |
28 |
Correct |
3 ms |
1884 KB |
Output is correct |
29 |
Correct |
3 ms |
1852 KB |
Output is correct |
30 |
Correct |
3 ms |
1628 KB |
Output is correct |
31 |
Correct |
3 ms |
2396 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
0 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
0 ms |
348 KB |
Output is correct |
10 |
Correct |
0 ms |
348 KB |
Output is correct |
11 |
Correct |
0 ms |
348 KB |
Output is correct |
12 |
Correct |
0 ms |
348 KB |
Output is correct |
13 |
Correct |
0 ms |
344 KB |
Output is correct |
14 |
Correct |
0 ms |
348 KB |
Output is correct |
15 |
Correct |
0 ms |
348 KB |
Output is correct |
16 |
Correct |
0 ms |
348 KB |
Output is correct |
17 |
Correct |
0 ms |
348 KB |
Output is correct |
18 |
Correct |
0 ms |
348 KB |
Output is correct |
19 |
Correct |
0 ms |
348 KB |
Output is correct |
20 |
Correct |
0 ms |
348 KB |
Output is correct |
21 |
Correct |
0 ms |
348 KB |
Output is correct |
22 |
Correct |
0 ms |
348 KB |
Output is correct |
23 |
Correct |
2 ms |
860 KB |
Output is correct |
24 |
Correct |
2 ms |
860 KB |
Output is correct |
25 |
Correct |
2 ms |
856 KB |
Output is correct |
26 |
Correct |
3 ms |
1628 KB |
Output is correct |
27 |
Correct |
3 ms |
1628 KB |
Output is correct |
28 |
Correct |
3 ms |
1884 KB |
Output is correct |
29 |
Correct |
3 ms |
1852 KB |
Output is correct |
30 |
Correct |
3 ms |
1628 KB |
Output is correct |
31 |
Correct |
3 ms |
2396 KB |
Output is correct |
32 |
Correct |
18 ms |
6840 KB |
Output is correct |
33 |
Correct |
17 ms |
7004 KB |
Output is correct |
34 |
Correct |
19 ms |
6900 KB |
Output is correct |
35 |
Correct |
76 ms |
27092 KB |
Output is correct |
36 |
Correct |
81 ms |
26960 KB |
Output is correct |
37 |
Correct |
74 ms |
26972 KB |
Output is correct |
38 |
Correct |
70 ms |
29124 KB |
Output is correct |
39 |
Correct |
72 ms |
28472 KB |
Output is correct |
40 |
Correct |
65 ms |
28344 KB |
Output is correct |
41 |
Correct |
78 ms |
34616 KB |
Output is correct |