Submission #1098609

#	Time	Username	Problem	Language	Result	Execution time	Memory
1098609		flyingkite	Museum (CEOI17_museum)	C++17	100 / 100	696 ms	746324 KiB

museum

#include <bits/stdc++.h>
using namespace std;
 
#define ll int
#define pll pair<int, int>
#define pb push_back
#define F first
#define S second  
#define all(x) (x).begin(), (x).end()
 
const ll N = 1e4 + 2;
const ll inf = 1e9;
const ll mod = 1e9 + 7;
const ll block = 350;
ll n,k,x;
vector<pll>adj[N];
ll dp[N][N][2], sz[N], f[2][N][2];
void dfs(ll u, ll par){
    for(auto v : adj[u]){
        if(v.F == par) continue;
        dfs(v.F, u);
    }
    for(int i = 0; i <= k;i++){
        for(int j = 0; j <= 1;j++){
            for(int l = 0; l <= 1;l++) f[j][i][l] = inf;
        }
    }
    f[1][1][0] = 0;
    sz[u] = 1;
    for(int idx = 0; idx < adj[u].size();idx++){
        ll v = adj[u][idx].F, w = adj[u][idx].S;
        if(v == par){
            for(int i = 0; i <= sz[u];i++){
                for(int j = 0; j <= 1;j++) swap(f[0][i][j], f[1][i][j]);
            }
            continue;
        }
        for(int i = 0; i <= sz[u];i++){
            for(int j = 0; j <= sz[v];j++){
                f[idx & 1][i + j][0] = min(f[idx & 1][i + j][0], f[(idx & 1) ^ 1][i + j][0]);
                f[idx & 1][i + j][0] = min(f[idx & 1][i + j][0], f[(idx & 1) ^ 1][i][0] + dp[v][j][0] + 2 * w);
                f[idx & 1][i + j][1] = min(f[idx & 1][i + j][1], f[(idx & 1) ^ 1][i][0] + dp[v][j][1] + w);
                f[idx & 1][i + j][1] = min(f[idx & 1][i + j][1], f[(idx & 1) ^ 1][i][1] + dp[v][j][0] + 2 * w);
                f[idx & 1][i + j][1] = min(f[idx & 1][i + j][1], f[(idx & 1) ^ 1][i + j][1]);
            }
        }
        sz[u] += sz[v];
    }
    
    for(int i = 0; i <= k;i++){
        for(int j = 0; j <= 1;j++) dp[u][i][j] = min(f[0][i][j], f[1][i][j]);
    }
    dp[u][0][0] = 0, dp[u][1][0] = 0, dp[u][1][1] = 0, dp[u][0][1] = 0; 
}
void to_thic_cau(){
    cin >> n >> k >> x;
    for(int i = 1; i <= n - 1;i++){
        ll u,v,c; cin >> u >> v >> c;
        adj[u].pb({v, c}); adj[v].pb({u, c});
    }
    dfs(x, 0);
    cout << min(dp[x][k][0], dp[x][k][1]) << '\n';
}
 
signed main()   
{  
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll tc = 1;
    //cin >> tc;
    while(tc--) to_thic_cau();
}

Compilation message (stderr)

museum.cpp: In function 'void dfs(int, int)':
museum.cpp:30:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int idx = 0; idx < adj[u].size();idx++){
      |                      ~~~~^~~~~~~~~~~~~~~

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