제출 #526731

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
526731		chicken337	Parkovi (COCI22_parkovi)	C++17	0 / 110	428 ms	41992 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MAXN = 200005;

int n, K, cur_val, put[MAXN], actual[MAXN];
vector<pair<int, int>> adj[MAXN];

pair<int, bool> dfs(int x, int par){
    int mx = 0, d_par = 0, c = 0, has = 0;
    for(auto& [nxt, wt] : adj[x]){
        if(nxt == par){
            d_par = wt;
            continue;
        }
        pair<int, bool> res = dfs(nxt, x);
        if(res.second) c = min(c, res.first), has = 1;
        else mx = max(mx, res.first);
    }
    if(has && mx + c <= 0){
        // cout << x << " returning " << (c + d_par > 0 ? d_par : c + d_par) << ' ' << (c+d_par <= 0) << endl;
        return {(c + d_par > 0 ? d_par : c + d_par), c+d_par <= 0};
    }
    if(mx + d_par > cur_val){
        put[x] = 1;
        // cout << x << " putting and returning " << (d_par - cur_val > 0 ? d_par : d_par - cur_val) << ' ' << 1 << endl;
        return {d_par - cur_val > 0 ? d_par : d_par - cur_val, 1};
    }
    // cout << x << " returning " << d_par + mx << " 0" << endl;
    return {d_par + mx, 0};
}

bool check(int val){
    // cout << "CHECKING " << val << endl;
    memset(put, 0, sizeof put);
    int cnt = 0; cur_val = val;
    dfs(0, -1);
    for(int i = 0; i < n; i ++)
        cnt += put[i];
    return cnt <= K;
}

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

    cin >> n >> K;
    for(int i = 1; i < n; i ++){
        int a, b, w; cin >> a >> b >> w;
        adj[a-1].emplace_back(b-1, w);
        adj[b-1].emplace_back(a-1, w);
    }

    int l = 0, r = 1e18, ans = -1;
    while(l <= r){
        int m = (l + r) >> 1;
        if(check(m)){
            ans = m; r = m-1;
            for(int i = 0; i < n; i ++)
                actual[i] = put[i];
        } else l = m+1;
    }

    cout << ans << '\n';
    set<int> numbers;
    int num_taken = 0;
    for(int i = 0; i < n; i ++)
        numbers.insert(i);
    for(int i = 0; i < n; i ++)
        if(actual[i]){
            cout << i+1 << ' ';
            numbers.erase(i);
            num_taken ++;
        }
    while(num_taken < K){
        cout << *numbers.begin()+1 << ' ';
        numbers.erase(numbers.begin());
        num_taken ++;
    }
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 60