제출 #1118780

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1118780		Cadoc	Museum (CEOI17_museum)	C++14	100 / 100	432 ms	170572 KiB

museum

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

#define ll long long
#define pii pair<int, int>
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define el cout << '\n'
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define N 10005

int n, k, r;
vector<pii> g[N];
vector<int> dp[N][2];

// dp(u, k, ok = 0/1) la tong do dai duong di ngan nhat di qua k dinh trong cay con goc u,
// ok = 0 la khong quay lai u va nguoc lai

inline void combineSubtree(vector<int> &Ans, vector<int> &a, vector<int> &b, int cost){
    while(sz(Ans) < sz(a) + sz(b) - 1) Ans.emplace_back(INF);

    for(int i=0; i<sz(a); ++i){
        for(int j=0; j<sz(b); ++j){
            Ans[i + j] = min(Ans[i + j], a[i] + b[j] + cost);
        }
    }
}

void dfs(int u, int p = -1){
    dp[u][0] = dp[u][1] = {0, 0};
    for(pii T:g[u]){
        int v = T.fi, w = T.se;
        if(v != p){
            dfs(v, u);

            vector<int> f[2];
            for(int i=0; i<2; ++i) f[i] = dp[u][i];

            combineSubtree(dp[u][0], f[0], dp[v][1], 2ll * w);
            combineSubtree(dp[u][0], f[1], dp[v][0], w);
            combineSubtree(dp[u][1], f[1], dp[v][1], 2ll * w);
        }
    }
}

void Solve(){
    cin >> n >> k >> r;
    for(int i=1; i<n; ++i){
        int u, v, w; cin >> u >> v >> w;
        g[u].emplace_back(v, w);
        g[v].emplace_back(u, w);
    }

    dfs(r);
    cout << dp[r][0][k];
}

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

    #define NAME "TASK"
    if(fopen(NAME".inp", "r")){
        freopen(NAME".inp", "r", stdin);
        freopen(NAME".out", "w", stdout);
    }

    Solve();
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

museum.cpp: In function 'int main()':
museum.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
museum.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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