Submission #804472

#	Time	Username	Problem	Language	Result	Execution time	Memory
804472		otarius	Xor Sort (eJOI20_xorsort)	C++17	40 / 100	7 ms	1008 KiB

xorsort

#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <cstring>
#include <queue>
#include <map>
#include <cmath>
#include <iomanip>
using namespace std;

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair <int, int>
#define ull unsigned long long

// #define int long long
// #define int unsigned long long

const ll inf = 1e9 + 7;
const ll weirdMod = 998244353;

vector<pii> ans;
bool get(int n, int k) {
    return ((n >> k) & 1);
}
void opr(int a, int b) {
    ans.pb({a, b});
}
void solve() {
    int n, s;
    cin >> n >> s;
    int arr[n + 1];
    for (int i = 1; i <= n; i++)
        cin >> arr[i];
    if (s == 2) {
        int lst = n;
        for (int bt = 19; bt >= 0; bt--) {
            int pos = -1;
            for (int i = 1; i <= lst; i++)
                if (get(arr[i], bt)) pos = i;
            if (pos == -1) continue;
            for (int i = pos + 1; i <= lst; i++) {
                if (!get(arr[i], bt)) {
                    opr(i, i - 1); arr[i] ^= arr[i - 1];
                }
            } for (int i = pos - 1; i >= 1; i--) {
                if (!get(arr[i], bt)) {
                    opr(i, i + 1); arr[i] ^= arr[i + 1];
                }
            }
            for (int i = 2; i <= lst; i++) {
                opr(i - 1, i); arr[i - 1] ^= arr[i];
            } --lst;
        }
    } else {
        int b[n + 1];
        for (int i = 1; i <= n; i++)
            b[i] = arr[i];
        for (int i = 1; i < n; i++) {
            opr(i, i + 1); arr[i] ^= arr[i + 1];
        } int lst = n;
        for (int i = 1; i <= n; i++) {
            int pos = 1;
            for (int j = 2; j <= lst; j++) {
                if (b[pos] < b[j]) pos = j;
            } for (int j = pos; j < lst; j++) {
                opr(j + 1, j); arr[j + 1] ^= arr[j];
            } for (int j = pos - 1; j >= 2; j--) {
                opr(j - 1, j); arr[j - 1] ^= arr[j];
            } for (int j = pos; j < lst; j++)
                swap(b[j], b[j + 1]);
            --lst;
        }
    }
    cout << ans.size() << '\n';
    for (auto [a, b] : ans) cout << a << ' ' << b << '\n';
}
int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
        cout << '\n';
    }
    return 0;
}

• Subtask 1: 0 / 25
• Subtask 2: 0 / 35
• Subtask 3: 40 / 40