Submission #1111864

#	Time	Username	Problem	Language	Result	Execution time	Memory
1111864		luvna	Museum (CEOI17_museum)	C++14	100 / 100	225 ms	140624 KiB

museum

#include<bits/stdc++.h>

#define all(v) v.begin(), v.end()
#define endl "\n"

using namespace std;

const int N = 1e4+15;
const int MOD = 1e9 + 7;

int n, k, root;
vector<pair<int,int>> adj[N];
vector<int> f[N], g[N];
int sz[N];

void dfs(int u, int p){
    f[u].resize(sz[u] + 1, MOD);
    g[u].resize(sz[u] + 1, MOD);
    f[u][1] = g[u][1] = 0;
    int siz = 1;
    for(auto [v, w] : adj[u]) if(v != p){
        dfs(v,u);
        for(int i = siz; i >= 1; i--){
            for(int j = sz[v]; j >= 1; j--){
                f[u][i+j] = min({f[u][i+j], f[u][i] + g[v][j] + 2*w, g[u][i] + f[v][j] + w});
                g[u][i+j] = min(g[u][i+j], g[u][i] + g[v][j] + 2*w);
            }
        }
        siz += sz[v];
    }
}

void luvna(int u, int p){
    sz[u] = 1;
    for(auto [v, w] : adj[u]) if(v != p){
        luvna(v,u);
        sz[u] += sz[v];
    }
}

void solve(){
    cin >> n >> k >> root;

    for(int i = 1; i < n; i++){
        int u, v, w; cin >> u >> v >> w;
        adj[u].push_back({v,w});
        adj[v].push_back({u,w});
    }

    luvna(root,-1);
    dfs(root,-1);

    cout << min(g[root][k], f[root][k]);
}

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

    #define task "task"

    if(fopen(task".INP", "r")){
        freopen(task".INP", "r", stdin);
        freopen(task".OUT", "w", stdout);
    }

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

Compilation message (stderr)

museum.cpp: In function 'void dfs(int, int)':
museum.cpp:21:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   21 |     for(auto [v, w] : adj[u]) if(v != p){
      |              ^
museum.cpp: In function 'void luvna(int, int)':
museum.cpp:35:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   35 |     for(auto [v, w] : adj[u]) if(v != p){
      |              ^
museum.cpp: In function 'int main()':
museum.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
museum.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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