Submission #1105123

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105123		TrinhKhanhDung	Museum (CEOI17_museum)	C++14	100 / 100	247 ms	278820 KiB

museum

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 1e4 + 10;

int N, K, S;
vector<pair<int, int>> adj[MAX];
vector<ll> dp[MAX][2];
int cnt[MAX];

void dfs(int u, int p = -1){
    cnt[u] = 1;
    for(auto o: adj[u]){
        int v = o.fi;
        if(v == p) continue;
        dfs(v, u);
        cnt[u] += cnt[v];
    }

    for(int i = 0; i < 2; i++){
        dp[u][i].resize(cnt[u] + 3, oo);
    }

    dp[u][1][1] = dp[u][0][1] = 0;

    int cur = 1;
    for(auto o: adj[u]){
        int v = o.fi;
        int c = o.se;
        if(v == p) continue;

        for(int i = cur; i >= 1; i--){
            for(int j = cnt[v]; j >= 1; j--){
                minimize(dp[u][0][i + j], dp[u][0][i] + dp[v][0][j] + 2 * c);
                minimize(dp[u][1][i + j], dp[u][1][i] + dp[v][0][j] + 2 * c);
                minimize(dp[u][1][i + j], dp[u][0][i] + dp[v][1][j] + c);
            }
        }

        cur += cnt[v];

        for(int i = 0; i < 2; i++){
            dp[v][i].clear();
        }
    }
}

void solve(){
    cin >> N >> K >> S;
    for(int i = 1; i < N; i++){
        int u, v, c; cin >> u >> v >> c;
        adj[u].push_back({v, c});
        adj[v].push_back({u, c});
    }

    dfs(S);
    cout << dp[S][1][K] << '\n';
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//     freopen("btower.inp","r",stdin);
//     freopen("btower.out","w",stdout);

    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }

    return 0;
}

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