Submission #707949

#	Time	Username	Problem	Language	Result	Execution time	Memory
707949		josanneo22	Xor Sort (eJOI20_xorsort)	C++17	100 / 100	9 ms	1024 KiB

xorsort

#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;
 
const int maxn = 1005;
vector<int> a(maxn);
vector<pair<int, int> > v;
void go(int x, int y) { a[x] ^= a[y]; v.push_back({ x, y }); }
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, s; cin >> n >> s;
    for (int i = 0; i < n; i++) cin >> a[i];
    if (s == 1)
    {
        vector<int> b = a; b.resize(n);
        for (int i = n - 1; i > 0; i--)
        {
            for (int j = 0; j <= i && j < n - 1; j++) go(j, j + 1);
            int mi = max_element(b.begin(), b.end()) - b.begin();
            for (int j = mi; j < i; j++) go(j + 1, j);
            for (int j = mi - 1; j > 0; j--) go(j - 1, j);
            b.erase(b.begin() + mi);
        }
        go(0, 1);
    }
    else
    {
        int m = n;
        for (int b = 19; b >= 0; b--)
        {
            int l = -1;
            for (int i = 0; i < m; i++) if (a[i] & (1 << b))
            {
                l = i;
                break;
            }
            if (l == -1) continue;
            for (int i = l; i < m - 1; i++)
                if (!(a[i + 1] & (1 << b))) go(i + 1, i);
            for (int i = l; i < m - 1; i++) go(i, i + 1);
            m--;
        }
    }
    cout << v.size() << "\n";
    for (pair<int, int> i : v) cout << i.first+1 << " " << i.second+1 << "\n";
    //for (int i = 0; i < n; i++) cout << a[i] << " ";
    //cout << "\n";
    return 0;
}

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