Submission #465591

#	Time	Username	Problem	Language	Result	Execution time	Memory
465591		kilikuma	Xor Sort (eJOI20_xorsort)	C++14	65 / 100	11 ms	1272 KiB

xorsort

#include <bits/stdc++.h>
 
std::mt19937 rnd(std::chrono::steady_clock::now().time_since_epoch().count());
 
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int n, S;
    std::cin >> n >> S;
    
    std::vector<int> a(n);
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
    }
    
    std::vector<std::pair<int, int>> ans;
        
    if (S == 1) {
        auto swap = [&](int i, int j) {
            ans.emplace_back(i, j);
            ans.emplace_back(j, i);
            ans.emplace_back(i, j);
            a[i] ^= a[j];
            a[j] ^= a[i];
            a[i] ^= a[j];
        };
        while (!std::is_sorted(a.begin(), a.end())) {
            for (int j = 1; j < n; j++) {
                if (a[j - 1] > a[j]) {
                    swap(j - 1, j);
                }
            }
        }
    } else {
        auto swap = [&](int i, int j) {
            ans.emplace_back(i, j);
            ans.emplace_back(j, i);
            a[i] ^= a[j];
            a[j] ^= a[i];
        };
        for (int i = 19; i >= 0; i--) {
            for (int j = 0; j < n - 1; j++) {
                if (a[j] >> i & 1) {
                    if (a[j + 1] >> i & 1) {
                        ans.emplace_back(j, j + 1);
                        a[j] ^= a[j + 1];
                    } else {
                        swap(j + 1, j);
                    }
                }
            }
            if (a[n - 1] >> i & 1) n--;
        }
    }
    
    std::cout << ans.size() << "\n";
    for (auto [i, j] : ans) {
        std::cout << i + 1 << " " << j + 1 << "\n";
    }
    
    return 0;
}

Compilation message (stderr)

xorsort.cpp: In function 'int main()':
xorsort.cpp:58:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   58 |     for (auto [i, j] : ans) {
      |               ^

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