Submission #1300324

#	Time	Username	Problem	Language	Result	Execution time	Memory
1300324		jahongir	Museum (CEOI17_museum)	C++20	100 / 100	272 ms	151720 KiB

museum

#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")


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

#define ll long long
#define pii pair<int,int>
#define pll pair<ll,ll>
#define vi vector<int>
#define pb push_back
#define all(a) a.begin(),a.end()



const int mxn = 10001, inf = 1e9;
vector<pii> g[mxn];
vector<int> dp[mxn], dp2[mxn];
int sub[mxn];
int n,k,r;


void dfs(int u, int p){
    sub[u] = 1;
    dp[u].resize(2,0);
    dp2[u].resize(2,0);

    for(auto [v,c] : g[u]) if(v!=p){
        dfs(v,u);

        dp[u].resize(min(sub[u]+sub[v]+1,k+1),inf);
        dp2[u].resize(min(sub[u]+sub[v]+1,k+1),inf);

        for(int i = min(sub[u]+sub[v],k); i; i--) 
            for(int j = max(1,i-sub[v]); j <= min(i,sub[u]); j++){
                dp[u][i] = min(dp[u][i],dp[u][j] + dp[v][i-j] + 2*c);
                dp2[u][i] = min(dp2[u][i],dp[u][j] + dp2[v][i-j] + c);
                dp2[u][i] = min(dp2[u][i],dp2[u][j] + dp[v][i-j] + 2*c);
            }

        sub[u] += sub[v];
    }
}



void solve(){
    cin >> n >> k >> r;
    for(int i = 1; i < n; i++){
        int u,v,c; cin >> u >> v >> c;
        g[u].pb({v,c});
        g[v].pb({u,c});
    }

    dfs(r,r);

    cout << dp2[r][k];
}


signed main(){
    cin.tie(0)->sync_with_stdio(0);
    int t = 1;
    // cin >> t;
    while(t--){solve();}
}

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