Submission #1208131

#	Time	Username	Problem	Language	Result	Execution time	Memory
1208131		trufanov.p	Abracadabra (CEOI22_abracadabra)	C++20	10 / 100	1917 ms	589824 KiB

Main

#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <string>
#include <queue>
#include <unordered_set>
#include <deque>
#include <numeric>
#include <cmath>
#include <unordered_map>

using namespace std;

#pragma GCC optimize("O3")
#pragma GCC optimization("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

typedef long long ll;

ll p = 234571, Mod = 2e9 + 11;

ll hash_array(const vector<int>& a) {
    ll h = 0;
    for (int x : a) {
        h = (h * p + x) % Mod;
    }
    return h;
}

void riffle(vector<int>& a) {
    int n = a.size();
    vector<int> a1, a2;
    for (int i = 0; i < n / 2; ++i) {
        a1.push_back(a[i]);
        a2.push_back(a[i + n / 2]);
    }
    int it1 = 0, it2 = 0;
    while (it1 < n / 2 && it2 < n / 2) {
        if (a1[it1] < a2[it2]) {
            a[it1 + it2] = a1[it1];
            it1++;
        } else {
            a[it1 + it2] = a2[it2];
            it2++;
        }
    }
    while (it1 < n / 2) {
        a[it1 + it2] = a1[it1];
        it1++;
    }
    while (it2 < n / 2) {
        a[it1 + it2] = a2[it2];
        it2++;
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, q;
    cin >> n >> q;
    vector<int> p(n);
    for (int i = 0; i < n; ++i) {
        cin >> p[i];
    }
    vector<vector<int>> save;
    save.push_back(p);
    unordered_map<ll, int> t;
    t[hash_array(p)] = 0;
    int cur_t = 1;
    int preper = -1, per = -1;
    while (true) {
        riffle(p);
        ll h = hash_array(p);
        if (t.count(h)) {
            preper = t[h] - 1;
            per = cur_t - t[h];
            break;
        }
        save.push_back(p);
        t[h] = cur_t;
        cur_t++;
    }
    for (int _ = 0; _ < q; ++_) {
        int t, pos;
        cin >> t >> pos;
        pos--;
        if (t <= preper) {
            cout << save[t][pos] << '\n';
        } else {
            t -= preper;
            t %= per;
            cout << save[preper + 1 + t][pos] << '\n';
        }
    }
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 40
• Subtask 3: 0 / 25
• Subtask 4: 0 / 25