Submission #1101946

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101946		vjudge1	Museum (CEOI17_museum)	C++17	100 / 100	549 ms	783692 KiB

museum

#include<bits/stdc++.h>
using namespace std;
const int N = 10000 + 2;
const int inf = 1 << 28;
int sz[N];
int dp[N][2][N];
vector<pair<int, int>> g[N];
void calc_dp(int u, int p) {
	sz[u] = 1;
	for (auto &[v, c]: g[u]) {
		if (v == p) continue;
		calc_dp(v, u);
		sz[u] += sz[v]; 
	}
	for (int i = 0; i <= sz[u]; i++) dp[u][0][i] = dp[u][1][i] = inf;
	int len = 1;
	dp[u][0][0] = dp[u][1][0] = 0;
	dp[u][0][1] = dp[u][1][1] = 0;
	for (auto &[v, c]: g[u]) {
		if (v == p) continue;
		len += sz[v];
		for (int i = len; i >= 0; i--) {
			for (int j = max(0, i - (len - sz[v])); j <= min(i, sz[v]); j++) {
				dp[u][0][i] = min(dp[u][0][i], dp[u][1][i - j] + dp[v][0][j] + c);
				dp[u][0][i] = min(dp[u][0][i], dp[u][0][i - j] + dp[v][1][j] + c + c);
				dp[u][1][i] = min(dp[u][1][i], dp[u][1][i - j] + dp[v][1][j] + c + c);
			}
		}
	}
}
void solve() {
	int n, k, x;
	cin >> n >> k >> x;
	for (int i = 2; i <= n; i++) {
		int u, v, c;
		cin >> u >> v >> c;
		g[u].push_back({v, c});
		g[v].push_back({u, c});
	}
	calc_dp(x, 0);
	cout << dp[x][0][k] << '\n';
}

int32_t main() {
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    solve();
    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 25 / 25
• Subtask 3: 35 / 35
• Subtask 4: 20 / 20