Submission #218620

#	Time	Username	Problem	Language	Result	Execution time	Memory
218620		toxic_hack	Museum (CEOI17_museum)	C++14	100 / 100	775 ms	784696 KiB

museum

// g++ -std=c++14

/*

Today might be the chance to grasp the chance to let your talent bloom.
May be tomorrow, the day after, or next year...
May be even when you are 30. I'm not sure if physique has anything to do with it
but if you think that it will never come, it probably never will.

- Tooru Oikawa.

*/


#include<bits/stdc++.h>

typedef long long ll;
typedef long double lld;
using namespace std;

#define endl "\n"
#define fi first
#define se second
#define MEMS(a,b) memset(a,b,sizeof(a))
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define __ freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);
#define all(c) c.begin(),c.end()
#define pii pair<int, int>

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
	uniform_int_distribution<int> uid(l, r);
	return uid(rng);
}

#define tr(...) cout<<__FUNCTION__<<' '<<__LINE__<<" = ";trace(#__VA_ARGS__, __VA_ARGS__)
template<typename S, typename T>
ostream& operator<<(ostream& out,pair<S,T> const& p){out<<'('<<p.fi<<", "<<p.se<<')';return out;}

template<typename T>
ostream& operator<<(ostream& out,vector<T> const& v){
ll l=v.size();for(ll i=0;i<l-1;i++)out<<v[i]<<' ';if(l>0)out<<v[l-1];return out;}

template <typename T>
ostream &operator<<(ostream &out, set<T> const &v) {
    for (auto i = v.begin(); i != v.end(); i++)
        out << (*i) << ' ';
    return out;
}
template <typename T>
ostream &operator<<(ostream &out, multiset<T> const &v) {
    for (auto i = v.begin(); i != v.end(); i++)
        out << (*i) << ' ';
    return out;
}
template <typename T, typename V>
ostream &operator<<(ostream &out, map<T, V> const &v) {
    for (auto i = v.begin(); i != v.end(); i++)
        out << "\n" << (i->first) <<  ":"  << (i->second);
    return out;
}

template<typename T>
void trace(const char* name, T&& arg1){cout<<name<<" : "<<arg1<<endl;}

template<typename T, typename... Args>
void trace(const char* names, T&& arg1, Args&&... args){
const char* comma = strchr(names + 1, ',');cout.write(names, comma-names)<<" : "<<arg1<<" | ";trace(comma+1,args...);}

const int N = 1e4 + 2;
vector<vector<pii>> g(N);
int dp[2][N][N]; // 0-> for coming back, 1 -> staying
int n, k, x;
const int inf = 1e9 + 1;
int sub[N];

void dfs(int v, int p) {
    sub[v] = 1;
    dp[0][v][1] = 0;
    dp[1][v][1] = 0;
    for (auto u : g[v]) {
        if (u.fi == p) continue;
        dfs(u.fi, v);
        sub[v] += sub[u.fi];
    }
    int c = 1;
    // for (auto u : g[v]) {
    //     if (u.fi == p) continue;
    //     c += sub[u.fi];
    //     c = min(c, k);
    //     for (int j = c; j > 1; j--) {
    //         for (int i = 0; i <= min(sub[u.fi], k) && j - i >= 0; i++) {
    //             dp[1][v][j] = min(dp[1][v][j], dp[1][u.fi][i] + dp[0][v][j - i] + u.se);
    //             dp[1][v][j] = min(dp[1][v][j], dp[0][u.fi][i] + dp[1][v][j - i] + (u.se) * 2);
                
    //             dp[0][v][j] = min(dp[0][v][j], dp[0][u.fi][i] + dp[0][v][j - i] + (u.se * 2));
    //         }
    //     }
    // }
    for (auto u : g[v]) {
        if (u.fi == p) continue;
        for (int j = c; j >= 1; j--) {
            for (int i = 0; i <= min(sub[u.fi], k) && j + i <= k; i++) {
                dp[1][v][j + i] = min(dp[1][v][j + i], dp[1][u.fi][i] + dp[0][v][j] + u.se);
                dp[1][v][j + i] = min(dp[1][v][j + i], dp[0][u.fi][i] + dp[1][v][j] + 2 * u.se);

                dp[0][v][j + i] = min(dp[0][v][j + i], dp[0][u.fi][i] + dp[0][v][j] + 2 * u.se);
            }
        }
        c += sub[u.fi];
    }
    dp[0][v][0] = dp[1][v][0] = 0;
    // tr(v);
    // for (int i = 1; i <= k; i++) {
    //     cout << dp[0][v][i] << " ";
    // }
    // cout << endl;
    // for (int i = 1; i <= k; i++) {
    //     cout << dp[1][v][i] << " ";
    // }
    // cout << endl;
}

int solve() {
    for (int i = 0; i < N; i++) 
        for (int j = 0; j < N; j++) 
            for (int k = 0; k < 2; k++) 
                dp[k][i][j] = inf;

    cin >> n >> k >> x;
    for (int i = 0; i < n - 1; i++) {
        int v, u, w;
        cin >> v >> u >> w;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    dfs(x, 0);
    cout << dp[1][x][k] << endl;
    return 0;
}

int32_t main(){ _
    int t;
    // cin >> t;
    t = 1;
    while (t--) solve();
}

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