Submission #385611

#	Time	Username	Problem	Language	Result	Execution time	Memory
385611		vishesh312	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	293 ms	39788 KiB

ballmachine

#include "bits/stdc++.h"
using namespace std;
/*
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using ordered_set = tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>;
*/

#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()

using ll = long long;
const int mod = 1e9+7;

vector<vector<int>> adj, up;
vector<int> par, submn, tout, depth;
vector<bool> boulder;
set<pair<int, int>> s;
int LOG = 0, timer = 0;

void dfs1(int u, int p = -1) {
    submn[u] = u;
    for (int v : adj[u]) {
        if (v != p) {
            depth[v] = depth[u] + 1;
            dfs1(v, u);
            submn[u] = min(submn[u], submn[v]);
        }
    }
}

void dfs2(int u, int p = -1) {
    set<pair<int, int>> curs;
    for (int v : adj[u]) {
        if (v != p) {
            curs.insert({submn[v], v});
        }
    }
    for (auto pr : curs) {
        dfs2(pr.second, u);
    }
    tout[u] = ++timer;
    s.insert({tout[u], u});
}

void solve(int tc) {
    int n, q;
    cin >> n >> q;
    boulder.resize(n); adj.resize(n); up.resize(n); submn.resize(n); tout.resize(n); par.resize(n); depth.resize(n);
    int root = -1;
    while ((1 << LOG) <= n) ++LOG;
    for (auto &x : up) x.resize(LOG);
    for (int i = 0; i < n; ++i) {
        int p;
        cin >> p;
        if (p == 0) {
            root = i;
            continue;
        }
        --p;
        par[i] = p;
        adj[p].push_back(i);
        adj[i].push_back(p);
    }
    for (int i = 0; i < n; ++i) up[i][0] = par[i];
    up[root][0] = root;
    for (int l = 1; l < LOG; ++l) {
        for (int i = 0; i < n; ++i) {
            up[i][l] = up[up[i][l-1]][l-1];
        }
    }
    dfs1(root);
    dfs2(root);
    while (q--) {
        int a, b;
        cin >> a >> b;
//      cerr << "a b : " << a << " " << b << '\n';
        if (a == 1) {
            pair<int, int> cur;
            for (int i = 0; i < b; ++i) {
                cur = *s.begin();
                auto it = s.begin();
                s.erase(it);
                boulder[cur.second] = true;
            }
            cout << cur.second+1 << '\n';
        } else {
            --b;
            int cur = LOG-1;
            int dist = 0;
            while (cur >= 0) {
                if (depth[b] >= (1<<cur) and boulder[up[b][cur]]) {
//                  cout << "b cur up[b][cur] : " << b << " " << cur << " " << up[b][cur] << '\n';
                    b = up[b][cur];
                    dist ^= (1<<cur);
//                  cout << "b : " << b << '\n';
                }
                --cur;
            }
            s.insert({tout[b], b});
            boulder[b] = false;
            cout << dist << '\n';
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    int tc = 1;
    //cin >> tc;
    for (int i = 1; i <= tc; ++i) solve(i);
    return 0;
}

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