Submission #755465

#	Time	Username	Problem	Language	Result	Execution time	Memory
755465		dxz05	Ball Machine (BOI13_ballmachine)	C++17	7.64 / 100	1097 ms	40064 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 = 1e6 + 3e2;

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

int sub_min[N];
void dfs0(int v){
    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 last = v, cnt = 0;
            while (v != 0 & flag[v]){
                cnt++;
                last = v;
                v = p[v];
            }

            flag[last] = 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 'void solve()':
ballmachine.cpp:91:22: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   91 |             while (v != 0 & flag[v]){
      |                    ~~^~~~
ballmachine.cpp: In function 'int main()':
ballmachine.cpp:106:13: warning: unused variable 'startTime' [-Wunused-variable]
  106 |     clock_t startTime = clock();
      |             ^~~~~~~~~

• Subtask 1: 1.9230769230769231 / 25
• Subtask 2: 0 / 30
• Subtask 3: 5.714285714285714 / 40
• Subtask 4: 0 / 5