Submission #579935

#	Time	Username	Problem	Language	Result	Execution time	Memory
579935		drdilyor	Xor Sort (eJOI20_xorsort)	C++17	0 / 100	1 ms	212 KiB

xorsort

#if defined(ONPC) && !defined(_GLIBCXX_ASSERTIONS)
    #define _GLIBCXX_ASSERTIONS
#endif
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#ifdef ONPC
    #include "t_debug.cpp"
#else
    #define debug(...) 42
#endif
#define allit(a) (a).begin(), (a).end()
#define sz(a) ((int) (a).size())

using namespace std;
using ll = long long;
using vi = vector<int>;
namespace pd = __gnu_pbds;
template<typename K>
using ordered_set = pd::tree<K, pd::null_type, less<int>, pd::rb_tree_tag, pd::tree_order_statistics_node_update>;
template<typename... T>
using gp_hash_table = pd::gp_hash_table<T...>;//simple using statement gives warnings

const int INF = 1e9;
const ll INFL = 1e18;
const int N = 1e5;
const int K = 10; // 20
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rng(RANDOM);

int solve() {
    int n, s; cin >> n >> s;
    vi a(n); for (auto& i : a) cin >> i;
    vector<pair<int,int>> res;
#define DO(i, j) {res.emplace_back(i, j); a[i] ^= a[j];}
    auto print = [&]() {
        for (int i = 0; i < n; i++) cerr << bitset<K>(a[i]) << ' ';
        cerr << endl;
    };

    for (int b = K-1; b >= 0; b--) {
        //carry bit to the end
        int end = n-1;
        for (int i = 0; i < end; i++) {
            if (a[i] & (1<<b)) {
                if (! (a[i+1] & (1 << b)))
                    DO(i+1, i);
            }
        }
        debug(a, end);
    }

#ifdef ONPC
    debug(a);
    for (int i = 0; i < n-1; i++) {
        assert(s == 1 ? a[i] < a[i+1] : a[i] <= a[i+1]);
    }
#endif
//#ifndef ONPC
    cout << res.size() << '\n';
    for (auto [i, j] : res) cout << i+1 << ' ' << j+1 << '\n';
//#endif
    return 0;
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    int t = 1;
#ifdef ONPC
    cin >> t;
#endif
    while (t-- && cin) {
        if (solve()) break;
        #ifdef ONPC
            cout << "____________________" << endl;
        #endif
    }
    return 0;
}

Compilation message (stderr)

xorsort.cpp: In function 'int solve()':
xorsort.cpp:10:24: warning: statement has no effect [-Wunused-value]
   10 |     #define debug(...) 42
      |                        ^~
xorsort.cpp:50:9: note: in expansion of macro 'debug'
   50 |         debug(a, end);
      |         ^~~~~
xorsort.cpp:36:10: warning: variable 'print' set but not used [-Wunused-but-set-variable]
   36 |     auto print = [&]() {
      |          ^~~~~

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