#include <bits/stdc++.h>
#define int long long
using namespace std;
const int kN = 2e5;
const int INF = 1e18L;
vector<pair<int, int>> g[1 + kN];
int N, depth[1 + kN], sol[kN];
bitset<1 + kN> mark, covered;
void maxSelf(int &x, int y) {
if (x < y) {
x = y;
}
}
void minSelf(int &x, int y) {
if (y < x) {
x = y;
}
}
int dfs(int u, int par, int radius) {
if ((int)g[u].size() == 1 && par) {
return 0;
}
int mx = -INF, mn = INF;
for (auto it : g[u]) {
int v, w;
tie(v, w) = it;
if (v != par) {
int ret = dfs(v, u, radius);
if (ret == 0 && covered[v]) { // v este acoperit si nimic din subarborele sau nu ma mai poate ajuta mai mult decat u
maxSelf(mx, 0);
minSelf(mn, 0);
continue;
}
if (ret < 0 && ret + w <= 0) { // u este acoperit
covered[u] = true;
}
if (ret < 0 && ret + w > 0) { // v sigur e acoperit si incepand de la u nu se mai acopera nimic nou, deci "resetez"
ret = 0;
} else { // creste distanta fata de ultimul nod marcat si mai mult
ret += w;
}
if (ret > radius) { // trebuie sa il marchez pe v acum ca sa acopere alte noduri nemarcate, pentru ca deja u nu poate ajuta
sol[N++] = v;
mark[v] = true;
covered[v] = true;
ret = min(-radius + w, 0LL); // aproape analog cu cazurile anterioare
if (w <= radius) {
covered[u] = true;
}
}
maxSelf(mx, ret);
minSelf(mn, ret);
}
}
if (mn < 0) {
return mn;
}
return mx;
}
bool check(int m, int k) {
N = 0;
mark.reset();
covered.reset();
if (dfs(1, 0, m) > 0) {
sol[N++] = 1;
mark[1] = true;
} else if (!covered[1]) {
sol[N++] = 1;
mark[1] = true;
}
return N <= k;
}
void testCase() {
int n, k;
cin >> n >> k;
for (int i = 1; i < n; ++i) {
int u, v, w;
cin >> u >> v >> w;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
}
int ans = 0, step = (1LL << 60);
while (step) {
if (!check(ans | step, k)) {
ans |= step;
}
step /= 2;
}
ans += 1;
check(ans, k);
for (int v = 1; v <= n && N < k; ++v) {
if (!mark[v]) {
sol[N++] = v;
}
}
cout << ans << '\n';
for (int i = 0; i < k; ++i) {
cout << sol[i] << ' ';
}
cout << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int tests = 1;
for (int tc = 1; tc <= tests; ++tc) {
testCase();
}
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5072 KB |
Output is correct |
2 |
Correct |
3 ms |
4948 KB |
Output is correct |
3 |
Correct |
3 ms |
5076 KB |
Output is correct |
4 |
Correct |
4 ms |
5028 KB |
Output is correct |
5 |
Correct |
3 ms |
5076 KB |
Output is correct |
6 |
Correct |
3 ms |
5028 KB |
Output is correct |
7 |
Incorrect |
3 ms |
5076 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
428 ms |
34424 KB |
Output is correct |
2 |
Correct |
461 ms |
35204 KB |
Output is correct |
3 |
Correct |
215 ms |
19536 KB |
Output is correct |
4 |
Incorrect |
1153 ms |
18824 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
490 ms |
35808 KB |
Output is correct |
2 |
Correct |
468 ms |
39128 KB |
Output is correct |
3 |
Correct |
523 ms |
37328 KB |
Output is correct |
4 |
Correct |
436 ms |
37300 KB |
Output is correct |
5 |
Correct |
466 ms |
41188 KB |
Output is correct |
6 |
Correct |
481 ms |
40180 KB |
Output is correct |
7 |
Correct |
515 ms |
41712 KB |
Output is correct |
8 |
Correct |
477 ms |
39648 KB |
Output is correct |
9 |
Correct |
477 ms |
39352 KB |
Output is correct |
10 |
Correct |
522 ms |
38656 KB |
Output is correct |
11 |
Correct |
416 ms |
37512 KB |
Output is correct |
12 |
Correct |
497 ms |
41848 KB |
Output is correct |
13 |
Correct |
531 ms |
41840 KB |
Output is correct |
14 |
Correct |
524 ms |
40384 KB |
Output is correct |
15 |
Correct |
528 ms |
37920 KB |
Output is correct |
16 |
Correct |
423 ms |
36484 KB |
Output is correct |
17 |
Correct |
439 ms |
36412 KB |
Output is correct |
18 |
Correct |
433 ms |
38144 KB |
Output is correct |
19 |
Correct |
431 ms |
38792 KB |
Output is correct |
20 |
Correct |
485 ms |
39604 KB |
Output is correct |
21 |
Correct |
453 ms |
38464 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5072 KB |
Output is correct |
2 |
Correct |
3 ms |
4948 KB |
Output is correct |
3 |
Correct |
3 ms |
5076 KB |
Output is correct |
4 |
Correct |
4 ms |
5028 KB |
Output is correct |
5 |
Correct |
3 ms |
5076 KB |
Output is correct |
6 |
Correct |
3 ms |
5028 KB |
Output is correct |
7 |
Incorrect |
3 ms |
5076 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |