Submission #1309455

#	Time	Username	Problem	Language	Result	Execution time	Memory
1309455		aaaaaaaa	Ball Machine (BOI13_ballmachine)	C++20	100 / 100	113 ms	30768 KiB

ballmachine

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

const int mxN = 1e5 + 10;
const int mxB = 21;

vector<int> adj[mxN];
int mn[mxN], ball[mxN], dp[mxN][mxB], depth[mxN];
vector<int> ord;

void dfs(int u = 1){
    mn[u] = u;
    depth[u] = depth[dp[u][0]] + 1;
    for(int j = 1; j < mxB; ++j){
        dp[u][j] = dp[dp[u][j - 1]][j - 1];
    }
    for(auto it : adj[u]){
        dp[it][0] = u;
        dfs(it);
        mn[u] = min(mn[u], mn[it]);
    }
}

void dfs2(int u = 1){
    vector<pair<int, int>> val;
    for(auto it : adj[u]){
        val.push_back({mn[it], it});
    }
    sort(val.begin(), val.end());
    for(auto it : val){
        dfs2(it.second);
    }
    ord.push_back(u);
}

int up_most(int u){
    for(int i = mxB - 1; i >= 0; --i){
        if(ball[dp[u][i]]){
            u = dp[u][i];
        }
    }
    return u;
}

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

    int n, q;
    cin >> n >> q;

    int root = 1;

    for(int i = 1, par; i <= n; ++i){
        cin >> par;
        adj[par].push_back(i);
        if(par == 0) root = i;
    } 
    
    dfs(root);
    dfs2(root);

    set<pair<int, int>> empty;

    vector<int> pos(n + 5, 0);

    for(int i = 0; i < (int) ord.size(); ++i){
        empty.insert({i, ord[i]});
        pos[ord[i]] = i;
    }

    auto remove = [&](int x) -> void {
        int top = up_most(x);
        empty.insert({pos[top], top});
        ball[top] = 0;
        cout << depth[x] - depth[top] << "\n";
    };

    while(q--){
        int t, k;
        cin >> t >> k;
        if(t == 1){
            int last = 0;
            while(k--){
                auto tp = *empty.begin();
                empty.erase(tp);
                last = tp.second;
                ball[tp.second] = 1;
            }
            cout << last << "\n";
        }else{
           remove(k);
        }
    }

    return 0;
}

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