#include <bits/stdc++.h>
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>*/
#define pb push_back
#define mp make_pair
#define sz(s) ((int)(s.size()))
#define all(s) s.begin(), s.end()
#define rep(i, a, n) for (int i = a; i <= n; ++i)
#define per(i, n, a) for (int i = n; i >= a; --i)
#define onlycin ios_base::sync_with_stdio(false); cin.tie(0)
#define F first
#define S second
using namespace std;
// using namespace __gnu_pbds;
typedef long long ll;
typedef unsigned long long ull;
/*typedef tree<
pair < int, int >,
null_type,
less< pair < int, int > >,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;*/
// find_by_order() order_of_key()
const int MAXN = (int)5e5+228;
const char nxtl = '\n';
const int mod = (int)1e9+7;
const double eps = (double)1e-7;
template<typename T> inline bool updmin(T &a, const T &b) {return a > b ? a = b, 1 : 0;}
template<typename T> inline bool updmax(T &a, const T &b) {return a < b ? a = b, 1 : 0;}
int n, dp[2][MAXN];
vector < pair < int, int > > g[MAXN];
void dfs(int v, int D = 0, int pr = -1) {
dp[0][v] = 0;
dp[1][v] = -mod;
vector < pair < int, int > > child;
for(auto &it : g[v]) {
int to = it.F;
if(pr == to) continue;
dfs(to, it.S, v);
child.pb({to, it.S});
}
// update dp[1]
if(pr != -1) {
int sum0 = 0;
for(auto &to : child) sum0 += max(dp[0][to.F], dp[1][to.F]);
for(auto &to : child) {
sum0 -= max(dp[0][to.F], dp[1][to.F]);
updmax(dp[1][v], sum0+D+to.S+dp[0][to.F]);
sum0 += max(dp[0][to.F], dp[1][to.F]);
}
}
// update dp[0]
for(auto &to : child) dp[0][v] += max(dp[0][to.F], dp[1][to.F]);
for(auto &to : child) {
for(auto &it : child) {
if(to.F == it.F) continue;
int sum = 0;
for(auto &k : child) {
if(k.F == to.F || k.F == it.F) continue;
sum += max(dp[0][k.F], dp[1][k.F]);
}
updmax(dp[0][v], sum + to.S + it.S + dp[0][to.F] + dp[0][it.F]);
}
updmax(dp[0][v], max(dp[1][to.F], dp[0][to.F]));
}
// cerr << v << ' '<< dp[0][v] << ' '<< dp[1][v] << nxtl;
}
int main() {
#ifdef accepted
freopen(".in", "r", stdin);
freopen(".out", "w", stdout);
#endif
onlycin;
cin >> n;
rep(i, 2, n) {
int x, y, z; cin >> x >> y >> z;
g[x].pb(mp(y, z)); g[y].pb(mp(x, z));
}
dfs(1);
int res = dp[0][1];
rep(root, 1, n) {
dfs(root);
// assert(res == dp[0][root]);
updmax(res, dp[0][root]);
}
cout << res << nxtl;
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
12156 KB |
Output is correct |
| 2 |
Correct |
13 ms |
12160 KB |
Output is correct |
| 3 |
Correct |
11 ms |
12160 KB |
Output is correct |
| 4 |
Correct |
11 ms |
12132 KB |
Output is correct |
| 5 |
Correct |
12 ms |
12160 KB |
Output is correct |
| 6 |
Incorrect |
12 ms |
12032 KB |
Output isn't correct |
| 7 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
12156 KB |
Output is correct |
| 2 |
Correct |
13 ms |
12160 KB |
Output is correct |
| 3 |
Correct |
11 ms |
12160 KB |
Output is correct |
| 4 |
Correct |
11 ms |
12132 KB |
Output is correct |
| 5 |
Correct |
12 ms |
12160 KB |
Output is correct |
| 6 |
Incorrect |
12 ms |
12032 KB |
Output isn't correct |
| 7 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
12156 KB |
Output is correct |
| 2 |
Correct |
13 ms |
12160 KB |
Output is correct |
| 3 |
Correct |
11 ms |
12160 KB |
Output is correct |
| 4 |
Correct |
11 ms |
12132 KB |
Output is correct |
| 5 |
Correct |
12 ms |
12160 KB |
Output is correct |
| 6 |
Incorrect |
12 ms |
12032 KB |
Output isn't correct |
| 7 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
13 ms |
12156 KB |
Output is correct |
| 2 |
Correct |
13 ms |
12160 KB |
Output is correct |
| 3 |
Correct |
11 ms |
12160 KB |
Output is correct |
| 4 |
Correct |
11 ms |
12132 KB |
Output is correct |
| 5 |
Correct |
12 ms |
12160 KB |
Output is correct |
| 6 |
Incorrect |
12 ms |
12032 KB |
Output isn't correct |
| 7 |
Halted |
0 ms |
0 KB |
- |
