Submission #1106363

#	Time	Username	Problem	Language	Result	Execution time	Memory
1106363		whoknow	Museum (CEOI17_museum)	C++17	100 / 100	591 ms	3400 KiB

museum

#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define MAXN 10005
#define ii pair<int,int>
#define bit(i,j) ((i>>j)&1)
#define sz(i) (int)i.size()
#define endl '\n'
using namespace std;
const int INF = 1e9;
int n, k, st;
vector<ii>g[MAXN];
namespace sub1
{
vector<int> dp[MAXN][2];
vector<int> combine(vector<int>x, vector<int>y, int w)
{
    vector<int>ans(sz(x) + sz(y) - 1, INF);
    for(int i = 1; i < sz(x); i++)
        for(int j = 0; j < sz(y); j++)
            if(i + j <= k)
                ans[i + j] = min(ans[i + j], x[i] + y[j] + w);
    return ans;
}
vector<int>mn(vector<int>x, vector<int>y)
{
    for(int i = 0; i < sz(x); i++)
        y[i] = min(x[i], y[i]);
    return y;
}
void dfs(int u, int p, int cost)
{
    dp[u][0] = {0, cost};
    dp[u][1] = {INF, cost};
    for(ii i : g[u])
    {
        int v = i.F, w = i.S;
        if(v == p)
            continue;
        dfs(v, u, w);
        dp[u][1] = mn(dp[u][1], combine(dp[u][1], dp[v][0], w));
        dp[u][1] = mn(dp[u][1], combine(dp[u][0], dp[v][1], 0));
        dp[u][0] = mn(dp[u][0], combine(dp[u][0], dp[v][0], w));
        vector<int>().swap(dp[v][0]);
        vector<int>().swap(dp[v][1]);
    }
}
void solve()
{
    dfs(st, 0, 0);
    cout << dp[st][1][k];
}
}
main()
{
    if(fopen("TEST.inp","r"))
    {
        freopen("TEST.inp","r",stdin);
        freopen("TEST.out","w",stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> k >> st;
    for(int i = 1; i < n; i++)
    {
        int x, y, z;
        cin >> x >> y >> z;
        g[x].push_back({y, z});
        g[y].push_back({x, z});
    }
    sub1::solve();
}

Compilation message (stderr)

museum.cpp:55:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   55 | main()
      | ^~~~
museum.cpp: In function 'int main()':
museum.cpp:59:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 |         freopen("TEST.inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
museum.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen("TEST.out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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