#include <bits/stdc++.h>
using namespace std;
const int NINF = numeric_limits<int>::min();
const int N = 200005;
int n, f[N][3], aux[3];
vector<pair<int, int>> aj[N];
void dfs(int v, int p_) {
f[v][0] = 0;
f[v][1] = f[v][2] = NINF;
for(const auto& [w, u] : aj[v]) {
if(u == p_) continue;
dfs(u, v);
for(int i = 0; i < 3; ++i) {
aux[i] = f[v][i];
f[v][i] = NINF;
}
for(int i = 0; i < 3; ++i) {
if(aux[i] != NINF) {
f[v][i] = aux[i] + max(max(f[u][0], f[u][2]), w + f[u][1]);
}
}
for(int i = 0; i < 2; ++i) {
if(aux[i] != NINF) {
f[v][i + 1] = max(f[v][i + 1], aux[i] + w + max(f[u][0], f[u][2]));
}
}
}
}
int main() {
scanf("%d", &n);
for(int _ = 1; _ < n; ++_) {
int u, v, w;
scanf("%d %d %d", &u, &v, &w);
aj[u].emplace_back(w, v);
aj[v].emplace_back(w, u);
}
dfs(1, -1);
printf("%d", max(f[1][0], f[1][2]));
return 0;
}
Compilation message
beads.cpp: In function 'int main()':
beads.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
35 | scanf("%d", &n);
| ~~~~~^~~~~~~~~~
beads.cpp:38:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
38 | scanf("%d %d %d", &u, &v, &w);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4948 KB |
Output is correct |
2 |
Correct |
4 ms |
5004 KB |
Output is correct |
3 |
Correct |
3 ms |
5004 KB |
Output is correct |
4 |
Correct |
3 ms |
5008 KB |
Output is correct |
5 |
Correct |
3 ms |
5008 KB |
Output is correct |
6 |
Incorrect |
3 ms |
5012 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4948 KB |
Output is correct |
2 |
Correct |
4 ms |
5004 KB |
Output is correct |
3 |
Correct |
3 ms |
5004 KB |
Output is correct |
4 |
Correct |
3 ms |
5008 KB |
Output is correct |
5 |
Correct |
3 ms |
5008 KB |
Output is correct |
6 |
Incorrect |
3 ms |
5012 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4948 KB |
Output is correct |
2 |
Correct |
4 ms |
5004 KB |
Output is correct |
3 |
Correct |
3 ms |
5004 KB |
Output is correct |
4 |
Correct |
3 ms |
5008 KB |
Output is correct |
5 |
Correct |
3 ms |
5008 KB |
Output is correct |
6 |
Incorrect |
3 ms |
5012 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
4948 KB |
Output is correct |
2 |
Correct |
4 ms |
5004 KB |
Output is correct |
3 |
Correct |
3 ms |
5004 KB |
Output is correct |
4 |
Correct |
3 ms |
5008 KB |
Output is correct |
5 |
Correct |
3 ms |
5008 KB |
Output is correct |
6 |
Incorrect |
3 ms |
5012 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |