Submission #1047981

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047981		ortsac	Ball Machine (BOI13_ballmachine)	C++17	47.88 / 100	78 ms	22728 KiB

ballmachine

#include <bits/stdc++.h>

using namespace std;

#define pii pair<int, int>
#define fr first
#define se second

const int MAXN = 1e5 + 10;
const int MAXLOG = 18;
int n, q;
int dad[MAXN];
int binl[MAXLOG][MAXN];
int minin[MAXN];
int ocupado[MAXN];
int h[MAXN];
vector<int> adj[MAXN];
int t = 0;
int order[MAXN];

void dfs(int node) {
    if (adj[node].size() == 0) minin[node] = node;
    else minin[node] = 0x3f3f3f3f;
    for (auto u : adj[node]) {
        h[u] = h[node] + 1;
        dfs(u);
        minin[node] = min(minin[node], minin[u]);
    }
}

void calcOrder(int node) {
    for (auto u : adj[node]) calcOrder(u);
    order[node] = ++t;
}

int lastB(int x) {
    for (int i = MAXLOG - 1; i >= 0; i--) {
        int maybe = binl[i][x];
        if (ocupado[maybe]) x = maybe; 
    }
    return x;
}

bool comp(int a, int b) {
    return minin[a] < minin[b];
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> q;
    int root;
    for (int i = 1; i <= n; i++) {
        cin >> dad[i];
        adj[dad[i]].push_back(i);
        if (dad[i] == 0) root = i;
    }
    dfs(root);
    for (int i = 1; i <= n; i++) {
        sort(adj[i].begin(), adj[i].end(), comp);
    }
    calcOrder(root);
    priority_queue<pii> ops;
    for (int i = 1; i <= n; i++) ops.push({-order[i], i});
    // lets calc binlift lesgooo
    for (int i = 1; i <= n; i++) {
        binl[0][i] = dad[i];
    }
    for (int j = 1; j < MAXLOG; j++) {
        for (int i = 1; i <= n; i++) {
            binl[j][i] = binl[j - 1][binl[j - 1][i]];
        }
    }
    // done bitches
    while (q--) {
        int t, x;
        cin >> t >> x;
        if (t == 2) {
            // beautiful
            int k = lastB(x);
            //cout << k << " its k\n";
            cout << h[x] - h[k] << "\n";
            ocupado[k] = 0;
            ops.push({-order[k], k});
            continue;
        }
        // insert x into 1
        int lst;
        while (x--) {
            int add = ops.top().se;
            //cout << "put " << add << "\n";
            ops.pop();
            lst = add;
            ocupado[add] = 1;
        }
        cout << lst << "\n";
    }
}

Compilation message (stderr)

ballmachine.cpp: In function 'int main()':
ballmachine.cpp:96:24: warning: 'lst' may be used uninitialized in this function [-Wmaybe-uninitialized]
   96 |         cout << lst << "\n";
      |                        ^~~~
ballmachine.cpp:62:14: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]
   62 |     calcOrder(root);
      |     ~~~~~~~~~^~~~~~

• Subtask 1: 1.9230769230769231 / 25
• Subtask 2: 12.857142857142858 / 30
• Subtask 3: 31.428571428571427 / 40
• Subtask 4: 1.6666666666666667 / 5