Submission #1207890

#	Time	Username	Problem	Language	Result	Execution time	Memory
1207890		countless	The Collection Game (BOI21_swaps)	C++20	100 / 100	2 ms	428 KiB

swaps

//
// --- Sample implementation for the task swaps ---
//
// To compile this program with the sample grader, place:
//     swaps.h swaps_sample.cpp sample_grader.cpp
// in a single folder and run:
//     g++ swaps_sample.cpp sample_grader.cpp
// in this folder.
//

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

typedef long long ll;
typedef long double ld;

const ll MOD = 998244353;
const ll INF = 1e18;
const ld EPS = 1e-12;

#define endl "\n"
#define sp <<" "<<
#define REP(i, a, b) for(ll i = a; i < b; i++)
#define dbg(x) cout << #x << " = " << x << endl
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fast_io() ios_base::sync_with_stdio(false); cin.tie(NULL)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

template <typename Key, typename Value>
using hash_map = unordered_map<Key, Value, custom_hash>;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// uniform_int_distribution<int>(a, b)(rng);
// shuffle(all(a), rng);

// concurrent sorts
// https://en.wikipedia.org/wiki/Batcher_odd%E2%80%93even_mergesort
void solve(int n, int v) {
    // 60%
    vector<int> at(n);
    iota(all(at), 1);

    vector<pair<int, int>> queries;
    auto in = [&](int x) -> bool {
        // return (0 < x and x <= n);
        return (0 <= x and x < n);
    };

    auto reset = [&]() -> void {
        queries.clear();
    };

    auto query = [&](int a, int b) -> void {
        if (!in(a) or !in(b)) {
            return;
        }

        schedule(at[a], at[b]);
        queries.push_back({a, b});
    };


    auto handle = [&]() -> void {
        vector<int> res = visit();
        int m = queries.size();
        for (int i = 0; i < m; i++) {
            auto [a, b] = queries[i];
            if (res[i] == 0) {
                swap(at[a], at[b]);
            }
        }
    };

    int pw2 = 1;
    while (pw2 < n) pw2 *= 2;

    for (int k = 2; k <= pw2; k *= 2) {
        for (int j = k; j > 1; j /= 2) {
            reset();

            if (j == k) {
                for (int i = 0; i < pw2; i++) {
                    int d = i % j;
                    int l = i + j - d - d - 1;
                    if (l > i) query(i, l);
                }
            }

            else {
                vector<bool> vis(n, false);
                for (int i = 0; i < pw2; i++) {
                    int l = i + (j / 2);
                    if (l > i and !vis[l] and !vis[i]) {
                        vis[i] = true, vis[l] = true;
                        query(i, l);
                    }
                }
            }


            handle();
        }
    }

    answer(at);
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3-1: 3 / 3
• Subtask 3-2: 2 / 2
• Subtask 4-1: 9 / 9
• Subtask 4-2: 6 / 6
• Subtask 5-1: 9 / 9
• Subtask 5-2: 6 / 6
• Subtask 6-1: 21 / 21
• Subtask 6-2: 14 / 14
• Subtask 7-1: 9 / 9
• Subtask 7-2: 6 / 6