Submission #1119588

#	Time	Username	Problem	Language	Result	Execution time	Memory
1119588		InvMOD	Museum (CEOI17_museum)	C++14	100 / 100	412 ms	308176 KiB

museum

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

#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define dbg(x) "[" #x " = " << (x) << "]"
///#define int long long

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}

const int N = 2e5+5;
const ll MOD = 1e9+7;
const ll INF = 1e18;


void solve()
{
    int n,k,start; cin >> n >> k >> start;

    vector<vector<pair<int,int>>> adj(n+1, vector<pair<int,int>>());
    FOR(i, 1, n-1){
        int u,v,c; cin >> u >> v >> c;
        adj[u].emplace_back(v, c);
        adj[v].emplace_back(u, c);
    }

    vector<int> sz; sz.resize(n+1);
    vector<vector<vector<ll>>> dp(n+1, vector<vector<ll>>(2, vector<ll>()));

    function<vector<vector<ll>>(vector<vector<ll>>&, vector<vector<ll>>&)> combine = [&](vector<vector<ll>>& dad, vector<vector<ll>>& child){
        vector<vector<ll>> combined(2, vector<ll>(sz(dad[0]) + sz(child[0]) - 1, INF));

        FOR(i, 0, sz(dad[0]) - 1){
            combined[0][i] = dad[0][i];
            combined[1][i] = dad[1][i];
        }

        FOR(i, 1, sz(child[0]) - 1){
            combined[0][i] = min(combined[0][i], child[0][i]);
            combined[1][i] = min(combined[1][i], child[1][i]);
        }

        FOR(i, 1, sz(dad[0]) - 1){
            FOR(j, 1, sz(child[0]) - 1){
                combined[0][i + j] = min(combined[0][i + j], dad[0][i] + child[0][j]);
                combined[1][i + j] = min(combined[1][i + j], dad[0][i] + child[1][j]);
                combined[1][i + j] = min(combined[1][i + j], dad[1][i] + child[0][j]);
            }
        }
        return combined;
    };

    auto dfs = [&](auto&& dfs, int x, int p) -> void{
        dp[x][0] = {(ll)1e12, (ll)0};
        dp[x][1] = {(ll)1e12, (ll)0};

        sz[x] = 1;
        for(pair<int,int> e : adj[x]){
            int v = e.first, w = e.second;
            if(v != p){
                dfs(dfs, v, x);
                FOR(i, 1, sz[v]){
                    dp[v][0][i] = dp[v][0][i] + 2ll * w;
                    dp[v][1][i] = dp[v][1][i] + 1ll * w;
                }

                sz[x] += sz[v];
                dp[x] = combine(dp[x], dp[v]);
            }
        }
    };

    dfs(dfs, start, - 1);
    cout << min(dp[start][1][k], dp[start][0][k]) <<"\n";
    return;
}

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

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

Compilation message (stderr)

museum.cpp: In function 'int main()':
museum.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
museum.cpp:99:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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