Submission #755476

#	Time	Username	Problem	Language	Result	Execution time	Memory
755476		dxz05	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	308 ms	26016 KiB

ballmachine

#pragma GCC optimize("Ofast,O3,unroll-loops")
#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair
//#define endl '\n'

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
const int MOD = 1e9 + 7;
const int N = 1e5 + 3e2;

int p[N];
vector<int> g[N];

int sub_min[N];
const int L = 17;
int up[N][L];

void dfs0(int v){
    up[v][0] = p[v];
    for (int i = 1; i < L; i++) up[v][i] = up[up[v][i - 1]][i - 1];

    sub_min[v] = v;
    for (int u : g[v]){
        dfs0(u);
        sub_min[v] = min(sub_min[v], sub_min[u]);
    }
}

int order[N], vertex[N];
int timer = 0;

void traversal(int v){
    sort(all(g[v]), [&](int x, int y){
        return sub_min[x] < sub_min[y];
    });

    for (int u : g[v]) traversal(u);

    timer++;
    order[v] = timer;
    vertex[timer] = v;
}

bool flag[N];

void solve(){
    int n, q;
    cin >> n >> q;

    int root = 0;
    for (int i = 1; i <= n; i++){
        cin >> p[i];
        if (p[i] != 0){
            g[p[i]].push_back(i);
        } else {
            root = i;
        }
    }

    dfs0(root);
    traversal(root);

    set<int> free;
    for (int i = 1; i <= n; i++) free.insert(i);

    while (q--){
        int t;
        cin >> t;
        if (t == 1){
            int k;
            cin >> k;

            int last = 0;
            while (k--){
                int v = *free.begin();
                free.erase(free.begin());
                v = vertex[v];
                flag[v] = true;
                last = v;
            }

            cout << last << endl;
        } else {
            int v;
            cin >> v;

            int cnt = 0;
            for (int i = L - 1; i >= 0; i--){
                int x = up[v][i];
                if (x != 0 && flag[x]){
                    v = x;
                    cnt += 1 << i;
                }
            }

            free.insert(order[v]);
            flag[v] = false;

            cout << cnt << endl;
        }
    }

}

int main(){
    clock_t startTime = clock();
    ios_base::sync_with_stdio(false);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int test_cases = 1;
//    cin >> test_cases;

    for (int test = 1; test <= test_cases; test++){
        // cout << (solve() ? "YES" : "NO") << endl;
        solve();
    }

#ifdef LOCAL
    cerr << "Time: " << int((double) (clock() - startTime) / CLOCKS_PER_SEC * 1000) << " ms" << endl;
#endif

    return 0;
}

Compilation message (stderr)

ballmachine.cpp: In function 'int main()':
ballmachine.cpp:116:13: warning: unused variable 'startTime' [-Wunused-variable]
  116 |     clock_t startTime = clock();
      |             ^~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40
• Subtask 4: 5 / 5