Submission #579932

#	Time	Username	Problem	Language	Result	Execution time	Memory
579932		thezomb1e	Xor Sort (eJOI20_xorsort)	C++17	65 / 100	10 ms	1364 KiB

xorsort

//thatsramen

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define eb emplace_back
#define pb push_back
#define ft first
#define sd second
#define pi pair<int, int>
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define dbg(...) dbg_out(__VA_ARGS__)

using ll = long long;
using ld = long double;
using namespace std;
using namespace __gnu_pbds;

//Constants
const ll INF = 5 * 1e18;
const int IINF = 2 * 1e9;
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
const ld PI = 3.14159265359;

//Templates
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) {return os << '(' << p.first << ", " << p.second << ')';}
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) {os << '['; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << ']';}
void dbg_out() {cerr << endl;}
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << H << ' '; dbg_out(T...); }
template<typename T> void mins(T& x, T y) {x = min(x, y);}
template<typename T> void maxs(T& x, T y) {x = max(x, y);}
template<typename T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using omset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

//order_of_key(k): number of elements strictly less than k
//find_by_order(k): k-th element in the set

void setPrec() {cout << fixed << setprecision(15);}
void unsyncIO() {cin.tie(0)->sync_with_stdio(0);}
void setIn(string s) {freopen(s.c_str(), "r", stdin);}
void setOut(string s) {freopen(s.c_str(), "w", stdout);}
void setIO(string s = "") {
    unsyncIO(); setPrec();
    if(s.size()) setIn(s + ".in"), setOut(s + ".out");
}

// #define TEST_CASES

void solve() {
    int n, s;
    cin >> n >> s;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    vector<pi> ans;
    if (s == 1) {
        auto op = [&](int x, int y) {
            x++; y++;
            ans.pb({y, x});
            ans.pb({x, y});
            ans.pb({y, x});
        };
        for (int i = 0; i < n; i++) {
            int min_i = i;
            for (int j = i; j < n; j++) {
                if (a[min_i] > a[j]) {
                    min_i = j;
                }
            }
            for (int j = min_i; j > i; j--) {
                swap(a[j - 1], a[j]);
                op(j - 1, j);
            }
        }
    } else {
        for (int i = 19; i >= 0 && n > 0; i--) {
            for (int j = 0; j < n - 1; j++) {
                if (a[j] & (1 << i)) {
                    if (!(a[j + 1] & (1 << i))) {
                        ans.pb({j + 2, j + 1});
                        a[j + 1] ^= a[j];
                    }
                    // 0 1
                    ans.pb({j + 1, j + 2});
                    a[j] ^= a[j + 1];
                }
            }
            if (a[n - 1] & (1 << i)) n--;
        }
    }
    cout << ans.size() << '\n';
    for (pi x : ans) {
        cout << x.ft << ' ' << x.sd << '\n';
    }
}

int main() {
    setIO();

    int tt = 1;
    #ifdef TEST_CASES
        cin >> tt;
    #endif

    while (tt--)
        solve();

    return 0;
}

Compilation message (stderr)

xorsort.cpp: In function 'void setIn(std::string)':
xorsort.cpp:44:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 | void setIn(string s) {freopen(s.c_str(), "r", stdin);}
      |                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
xorsort.cpp: In function 'void setOut(std::string)':
xorsort.cpp:45:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 | void setOut(string s) {freopen(s.c_str(), "w", stdout);}
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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