// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize ("Ofast,inline") // O1 - O2 - O3 - Os - Ofast
// #pragma GCC optimize ("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl
#define umap unordered_map
#define uset unordered_set
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;
const int INF = 1'000'000'007;
int k, n;
vpll graph[200005];
ll mid, max_dist[200005], to_park[200005], need[200005];
uset<ll> ans;
void dfs(ll u, ll p) {
max_dist[u] = 0;
to_park[u] = ll(1e16);
need[u] = 0;
trav(edge, graph[u]) {
ll v, w;
tie(v, w) = edge;
if (v != p) {
dfs(v, u);
need[u] += need[v];
max_dist[v] += w;
to_park[v] += w;
if (max_dist[v] > mid) {
max_dist[v] = -1e16;
to_park[v] = w;
++need[u];
// cout << "u = " << u + 1 << " v = " << v + 1 << endl;
ans.insert(v);
}
// cout<<max_dist[u]<<" "<<to_park[u]<<" "<<max_dist[v]<<" "<<to_park[v]<<endl;
if (max_dist[u] + to_park[v] <= mid) max_dist[u] = ll(-1e16);
if (max_dist[v] + to_park[u] > mid && max_dist[v] > max_dist[u]) max_dist[u] = max_dist[v];
if (to_park[v] < to_park[u]) to_park[u] = to_park[v];
}
}
if (!u && to_park[u] > mid) {
++need[u];
ans.insert(u);
}
// cout << "u = " << u + 1 << " p = " << p + 1 << " depth = " << depth << " weigth = " << weight << " max_dist = " << max_dist[u] << " to_park = " << to_park[u] << endl;
// cout << "ans = " << need[u] << endl << endl;
}
ll dists[200005];
void dfs2(int u, int p) {
if (ans.count(u)) dists[u] = 0;
trav(edge, graph[u]) {
ll v, w;
tie(v, w) = edge;
if (v != p) {
dfs2(v, u);
dists[u]=min(dists[u],dists[v]+w);
}
}
}
void dfs3(int u,int p) {
trav(edge, graph[u]) {
ll v, w;
tie(v, w) = edge;
if (v != p) {
dfs2(v, u);
dists[v]=min(dists[v],dists[u]+w);
}
}
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit);
cin >> n >> k;
rep(i, 1, n) {
int u, v, w;
cin >> u >> v >> w;
graph[--u].emplace_back(--v, w);
graph[v].emplace_back(u, w);
}
ll lo = 0, hi = ll(1e15);
while (lo != hi) {
mid = (lo + hi) / 2;
dfs(0, 0);
fill(dists, dists + 200005, ll(1e15));
dfs2(0,0);
dfs3(0,0);
ll max_dist = 0;
rep(i, 0, n) max_dist = max(max_dist, dists[i]);
if (max_dist > mid) ans.insert(0);
if (sz(ans) <= k)
hi = mid;
else
lo = mid + 1;
// debug(sz(ans));
// cout << endl;
ans.clear();
}
mid = lo;
dfs(0, 0);
fill(dists, dists + 200005, ll(1e16));
trav(val, ans) ans.insert(val);
dfs2(0,0);
dfs3(0,0);
ll max_dist = 0;
rep(i, 0, n) max_dist = max(max_dist, dists[i]);
// debug(max_dist);
if (max_dist > mid) ans.insert(0);
rep(i, 0, n) {
if (sz(ans) == k) break;
ans.insert(i);
}
cout << mid << endl;
trav(val, ans) cout << val + 1 << ' ';
cout << endl;
return 0;
}
Compilation message
Main.cpp: In function 'int main()':
Main.cpp:128:21: warning: comparison of integer expressions of different signedness: 'std::unordered_set<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
128 | if (sz(ans) <= k)
| ^
Main.cpp:151:21: warning: comparison of integer expressions of different signedness: 'std::unordered_set<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
151 | if (sz(ans) == k) break;
| ^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
7 ms |
6484 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
828 ms |
37400 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
892 ms |
38860 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
7 ms |
6484 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
