Submission #1252174

#	Time	Username	Problem	Language	Result	Execution time	Memory
1252174		rayan_bd	Museum (CEOI17_museum)	C++20	80 / 100	49 ms	23880 KiB

museum

#include <bits/stdc++.h>
using namespace std;

const int MAXN = 10005;
const int MAXK = 105;

#define int long long

const int INF = 5e18;

vector<pair<int, int>> adj[MAXN];
int dp[MAXN][MAXK][2];

int n, k, x;

void dfs(int u, int par) {
    dp[u][1][0] = 0;
    dp[u][1][1] = 0;

    for (auto [v, cost] : adj[u]) {
        if (v == par) continue;
        dfs(v, u);

        int tmp[MAXK][2];
        for (int i = 0; i <= k; ++i) tmp[i][0] = tmp[i][1] = INF;

        for (int i = 1; i <= k; ++i) {
            if (dp[u][i][0] == INF && dp[u][i][1] == INF) continue;
            for (int j = 0; j <= k - i; ++j) {
                if (dp[v][j][0] == INF && dp[v][j][1] == INF) continue;

                tmp[i + j][0] = min(tmp[i + j][0], dp[u][i][0] + dp[v][j][0] + 2 * cost);
                tmp[i + j][1] = min(tmp[i + j][1], dp[u][i][0] + dp[v][j][1] + cost);
                tmp[i + j][1] = min(tmp[i + j][1], dp[u][i][1] + dp[v][j][0] + 2 * cost);
            }
        }

        for (int i = 2; i <= k; ++i) {
            dp[u][i][0] = min(dp[u][i][0], tmp[i][0]);
            dp[u][i][1] = min(dp[u][i][1], tmp[i][1]);
        }
    }
}

signed main() {
	ios_base::sync_with_stdio(0);
	cin.tie(nullptr); cout.tie(nullptr);


    cin >> n >> k >> x;
    for (int i = 1; i < n; ++i) {
        int a, b, c;
        cin >> a >> b >> c;
        adj[a].emplace_back(b, c);
        adj[b].emplace_back(a, c);
    }

    for (int i = 1; i <= n; ++i)
        for (int j = 0; j <= k; ++j)
            dp[i][j][0] = dp[i][j][1] = INF;

    dfs(x, -1);

    int answer = min(dp[x][k][0], dp[x][k][1]);
    cout << answer << '\n';

    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 25 / 25
• Subtask 3: 35 / 35
• Subtask 4: 0 / 20