// Om Namah Shivaya
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a, b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a, b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
*/
const int MOD = 1e9 + 7;
const int N = 20 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
const int K = 20 + 5;
vector<pii> adj[N];
vector<int> subsiz(N);
int dp[N][K][2];
int dp2[K][2], dp3[K][2];
int k;
void dfs1(int u, int p) {
subsiz[u] = 1;
for (auto [v, w] : adj[u]) {
if (v == p) conts;
dfs1(v, u);
subsiz[u] += subsiz[v];
}
}
void dfs2(int u, int p) {
for (auto [v, w] : adj[u]) {
if (v == p) conts;
dfs2(v, u);
}
dp[u][1][1] = 0;
int curr_siz = 1;
for (auto [v, w] : adj[u]) {
if (v == p) conts;
rev(j1, curr_siz, 1) {
rep1(j2, subsiz[v]) {
amin(dp[u][j1 + j2][1], dp[u][j1][1] + dp[v][j2][1] + 2 * w);
}
}
curr_siz += subsiz[v];
}
memset(dp2, 0x3f, sizeof dp2);
memset(dp3, 0x3f, sizeof dp3);
dp2[1][0] = 0;
curr_siz = 1;
for (auto [v, w] : adj[u]) {
if (v == p) conts;
rev(j1, curr_siz, 1) {
rep1(j2, subsiz[v]) {
rep(t1, 2) {
rep(t2, 2) {
int t3 = t1 + (t2 ^ 1);
if (t3 >= 2) conts;
int cost = dp[v][j2][t2];
if (t2) cost += 2 * w;
else cost += w;
amin(dp3[j1 + j2][t3], dp2[j1][t1] + cost);
}
}
}
}
curr_siz += subsiz[v];
rep1(j, curr_siz) {
rep(t, 2) {
amin(dp2[j][t], dp3[j][t]);
dp3[j][t] = inf1;
}
}
}
rep1(j, curr_siz) {
dp[u][j][0] = min(dp2[j][0], dp2[j][1]);
}
}
void solve(int test_case)
{
int n, r; cin >> n >> k >> r;
rep1(i, n - 1) {
int u, v, w; cin >> u >> v >> w;
adj[u].pb({v, w}), adj[v].pb({u, w});
}
memset(dp, 0x3f, sizeof dp);
dfs1(r, -1);
dfs2(r, -1);
int ans = dp[r][k][0];
cout << ans << endl;
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
1 ms |
468 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
1 ms |
468 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Runtime error |
1 ms |
468 KB |
Execution killed with signal 11 |
7 |
Halted |
0 ms |
0 KB |
- |