#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10, inf = 1e9 + 5;
int dp[N][2], dpU[N][2], par[N], mx[N], E[N][3], MX1[N], MX2[N];
vector <int> g[N];
inline int adj(int v, int i) {return (v^E[i][0]^E[i][1]);}
void dfs(int v)
{
for (int i : g[v]) if (adj(v, i) != par[v]) {
par[adj(v, i)] = v;
dfs(adj(v, i));
mx[adj(v, i)] = max(dp[adj(v, i)][1] + E[i][2], dp[adj(v, i)][0]);
dp[v][0] += mx[adj(v, i)];
}
for (int i : g[v]) if (adj(v, i) != par[v]) {
if (dp[adj(v, i)][0] - mx[adj(v, i)] + E[i][2] > MX1[v])
MX2[v] = MX1[v], MX1[v] = dp[adj(v, i)][0] - mx[adj(v, i)] + E[i][2];
else if (dp[adj(v, i)][0] - mx[adj(v, i)] + E[i][2] > MX2[v])
MX2[v] = dp[adj(v, i)][0] - mx[adj(v, i)] + E[i][2];
dp[v][1] = max(dp[v][1], dp[v][0] - mx[adj(v, i)] + dp[adj(v, i)][0] + E[i][2]);
}
}
void dfsUp(int v, int w = 0)
{
int p = par[v];
if (p != 0) {
int x = dpU[p][0] + dp[p][0] - mx[v] + w;
dpU[v][0] = x - w, dpU[v][1] = x;;
if (MX1[p] != dp[v][0] - mx[v] + w) dpU[v][0] = max(dpU[v][0], MX1[p] + x);
else dpU[v][0] = max(dpU[v][0], MX2[p] + x);
dpU[v][0] = max(dpU[v][0], dpU[p][1] - dpU[p][0] + x);
}
for (int i : g[v]) if (adj(v, i) != p) dfsUp(adj(v, i), E[i][2]);
}
int32_t main()
{
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int n; cin >> n;
for (int i = 0; i < n - 1; i++) {
cin >> E[i][0] >> E[i][1] >> E[i][2];
g[E[i][0]].push_back(i);
g[E[i][1]].push_back(i);
}
for (int i = 1; i <= n; i++) MX1[i] = MX2[i] = dp[i][1] = dpU[i][1] = -inf;
dfs(1), dfsUp(1);
int ans = 0;
for (int i = 1; i <= n; i++) ans = max(ans, dp[i][0] + dpU[i][0]);
cout << ans << "\n";
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
5112 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
5112 KB |
Output is correct |
4 |
Correct |
6 ms |
4984 KB |
Output is correct |
5 |
Correct |
8 ms |
5108 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
6 ms |
5112 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
6 ms |
5116 KB |
Output is correct |
10 |
Correct |
6 ms |
5112 KB |
Output is correct |
11 |
Correct |
6 ms |
5112 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
5112 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
5112 KB |
Output is correct |
4 |
Correct |
6 ms |
4984 KB |
Output is correct |
5 |
Correct |
8 ms |
5108 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
6 ms |
5112 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
6 ms |
5116 KB |
Output is correct |
10 |
Correct |
6 ms |
5112 KB |
Output is correct |
11 |
Correct |
6 ms |
5112 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
13 |
Correct |
9 ms |
5084 KB |
Output is correct |
14 |
Correct |
8 ms |
5112 KB |
Output is correct |
15 |
Correct |
7 ms |
5112 KB |
Output is correct |
16 |
Correct |
4 ms |
5112 KB |
Output is correct |
17 |
Correct |
7 ms |
5112 KB |
Output is correct |
18 |
Correct |
6 ms |
5112 KB |
Output is correct |
19 |
Correct |
6 ms |
5112 KB |
Output is correct |
20 |
Correct |
6 ms |
5112 KB |
Output is correct |
21 |
Correct |
7 ms |
5112 KB |
Output is correct |
22 |
Correct |
6 ms |
5084 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
5112 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
5112 KB |
Output is correct |
4 |
Correct |
6 ms |
4984 KB |
Output is correct |
5 |
Correct |
8 ms |
5108 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
6 ms |
5112 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
6 ms |
5116 KB |
Output is correct |
10 |
Correct |
6 ms |
5112 KB |
Output is correct |
11 |
Correct |
6 ms |
5112 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
13 |
Correct |
9 ms |
5084 KB |
Output is correct |
14 |
Correct |
8 ms |
5112 KB |
Output is correct |
15 |
Correct |
7 ms |
5112 KB |
Output is correct |
16 |
Correct |
4 ms |
5112 KB |
Output is correct |
17 |
Correct |
7 ms |
5112 KB |
Output is correct |
18 |
Correct |
6 ms |
5112 KB |
Output is correct |
19 |
Correct |
6 ms |
5112 KB |
Output is correct |
20 |
Correct |
6 ms |
5112 KB |
Output is correct |
21 |
Correct |
7 ms |
5112 KB |
Output is correct |
22 |
Correct |
6 ms |
5084 KB |
Output is correct |
23 |
Correct |
10 ms |
5396 KB |
Output is correct |
24 |
Correct |
11 ms |
5372 KB |
Output is correct |
25 |
Correct |
12 ms |
5624 KB |
Output is correct |
26 |
Correct |
15 ms |
5752 KB |
Output is correct |
27 |
Correct |
16 ms |
5880 KB |
Output is correct |
28 |
Correct |
13 ms |
5880 KB |
Output is correct |
29 |
Correct |
11 ms |
5880 KB |
Output is correct |
30 |
Correct |
13 ms |
5880 KB |
Output is correct |
31 |
Correct |
10 ms |
6136 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
5112 KB |
Output is correct |
2 |
Correct |
6 ms |
5112 KB |
Output is correct |
3 |
Correct |
6 ms |
5112 KB |
Output is correct |
4 |
Correct |
6 ms |
4984 KB |
Output is correct |
5 |
Correct |
8 ms |
5108 KB |
Output is correct |
6 |
Correct |
6 ms |
5112 KB |
Output is correct |
7 |
Correct |
6 ms |
5112 KB |
Output is correct |
8 |
Correct |
6 ms |
5112 KB |
Output is correct |
9 |
Correct |
6 ms |
5116 KB |
Output is correct |
10 |
Correct |
6 ms |
5112 KB |
Output is correct |
11 |
Correct |
6 ms |
5112 KB |
Output is correct |
12 |
Correct |
6 ms |
5112 KB |
Output is correct |
13 |
Correct |
9 ms |
5084 KB |
Output is correct |
14 |
Correct |
8 ms |
5112 KB |
Output is correct |
15 |
Correct |
7 ms |
5112 KB |
Output is correct |
16 |
Correct |
4 ms |
5112 KB |
Output is correct |
17 |
Correct |
7 ms |
5112 KB |
Output is correct |
18 |
Correct |
6 ms |
5112 KB |
Output is correct |
19 |
Correct |
6 ms |
5112 KB |
Output is correct |
20 |
Correct |
6 ms |
5112 KB |
Output is correct |
21 |
Correct |
7 ms |
5112 KB |
Output is correct |
22 |
Correct |
6 ms |
5084 KB |
Output is correct |
23 |
Correct |
10 ms |
5396 KB |
Output is correct |
24 |
Correct |
11 ms |
5372 KB |
Output is correct |
25 |
Correct |
12 ms |
5624 KB |
Output is correct |
26 |
Correct |
15 ms |
5752 KB |
Output is correct |
27 |
Correct |
16 ms |
5880 KB |
Output is correct |
28 |
Correct |
13 ms |
5880 KB |
Output is correct |
29 |
Correct |
11 ms |
5880 KB |
Output is correct |
30 |
Correct |
13 ms |
5880 KB |
Output is correct |
31 |
Correct |
10 ms |
6136 KB |
Output is correct |
32 |
Correct |
49 ms |
8924 KB |
Output is correct |
33 |
Correct |
47 ms |
8824 KB |
Output is correct |
34 |
Correct |
47 ms |
8816 KB |
Output is correct |
35 |
Correct |
354 ms |
20260 KB |
Output is correct |
36 |
Correct |
278 ms |
20088 KB |
Output is correct |
37 |
Correct |
285 ms |
20168 KB |
Output is correct |
38 |
Correct |
169 ms |
20804 KB |
Output is correct |
39 |
Correct |
189 ms |
20720 KB |
Output is correct |
40 |
Correct |
200 ms |
20716 KB |
Output is correct |
41 |
Correct |
286 ms |
23920 KB |
Output is correct |