Submission #1025003

#	Time	Username	Problem	Language	Result	Execution time	Memory
1025003		Arpi2007	Xor Sort (eJOI20_xorsort)	C++14	100 / 100	7 ms	1100 KiB

xorsort

#include <iostream>
#include <queue>
#include <sstream>
#include <fstream>
#include <cmath>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <utility>
#include <stack>
#include <math.h>
#include <climits>
#include <stdlib.h>
#include <stdio.h>
#include <iomanip>
using namespace std;

#define ll long long
#define ld long double
#define ull unsigned long long
#define ub upper_bound
#define lb lower_bound 
#define ff first
#define ss second
#define mpr make_pair
#define vi vector<int>
#define vll vector<ll>
#define pii pair<int,int>
#define vpi vector<pii>
#define pb push_back
#define pob pop_back
#define mii map<int,int>
#define vpl vector<pair<ll, ll>>
#define pll pair<ll,ll>
#define all(v) v.begin(),v.end()
#define sz(x) x.size()
#define clr(x) x.clear()
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define print(x) cout<<"x="<<x<<endl;

ll MOD = 1e9 + 7;
ll MOD2 = 998244353;

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
}

/* void setprecision(int x) {

    cout.setf(ios::fixed | ios::showpoint);
    cout.precision(x);
} */

/*void setIO(string name = "") {
    if ((int)name.size() > 0) {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}*/

ll gcd(ll a, ll b)
{
    if (b == 0) {
        return a;
    }
    else {
        return gcd(b, a % b);
    }
}

int num(int n) {
    ll ans = 0;
    while (n != 0) {
        ans++;
        n /= 10;
    }
    return ans;
}

ll lcm(ll a, ll b) {
    return (a * b) / gcd(a, b);
}


ll factorial(ll n) {
    ll ans = 1;
    for (int i = 1; i <= n; i++) {
        ans *= i;
        ans %= MOD2;
    }
    return ans;
}

bool isPrime(int n)
{
    if (n <= 1) {
        return false;
    }
    if (n == 2) {
        return true;
    }
    for (int i = 2; i * i <= n; i++) {
        if (n % i == 0)
            return false;
    }
    return true;
}

int sumnum(int n) {
    int ans = 0;
    while (n != 0) {
        ans += n % 10;
        n /= 10;
    }
    return ans;
}

ll bpow_mod(ll a, ll b, ll mod)
{
    ll ans = 1;
    while (b) {
        if ((b & 1) == 1) {
            ans *= a;
            ans %= mod;
        }
        b >>= 1;
        a *= a;
        a %= mod;
    }
    return ans;
}

int highpow2(int n)
{
    int p = (int)log2(n);
    return (int)pow(2, p);
}

bool sortbysec(const pair<int, int>& a,
    const pair<int, int>& b)
{
    return (a.second < b.second);
}

void precalc() {
    return;
}


const int N = 3e5 + 10;
int a[1003];

void solve(){
    int n, s; cin >> n >> s;
    for(int i = 1; i <= n; ++i){
        cin >> a[i];
    }
    vpi ans;
    if(s == 1){
        int curmx = 0;
        for(int i = n; i >= 1; i--){
            int id = 1;
            for(int j = 1; j <= i; ++j){
                if((a[j] ^ curmx) > (a[id] ^ curmx)){
                    id = j;
                }
            }
           // cout << a[id] << endl;
            int minch = i;
            if(i == n){
                minch = n - 1;
            }
            for(int j = 1; j <= minch; ++j){
                ans.pb({j, j + 1});
                a[j] = (a[j + 1] ^ a[j]);
            }
            for(int j = id + 1; j <= i; ++j){
                ans.pb({j, j - 1});
                a[j] = (a[j - 1] ^ a[j]);
            }
            for(int j = id - 1; j >= 2; j--){
                ans.pb({j - 1, j});
                a[j - 1] = (a[j] ^ a[j - 1]);
            }
            curmx = a[i];
        }
    }
    else{
      //  int nn = 
        for(int i = 19; i >= 0; --i){
            bool f = false;
            for(int j = 1; j <= n - 1; ++j){
                if(a[j] & (1 << i)){
                    f = true;
                    if(a[j + 1] & (1 << i)){
                        ans.pb({j, j + 1});
                        a[j] = (a[j] ^ a[j + 1]);
                    }
                    else{
                        ans.pb({j + 1, j}); ans.pb({j, j + 1});
                        a[j + 1] = (a[j] ^ a[j + 1]);
                        a[j] = (a[j + 1] ^ a[j]);
                    }
                }
            }
            if(f){
                n--;
            }
        }
     }   
    cout << sz(ans) << "\n";
    for(auto i : ans){
        cout << i.ff << ' ' << i.ss << "\n";
    }
}

void cases() {
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
}

int main() {
   // setIO("hps");
    fastio();
    precalc();
    //setprecision(5);
    solve();
    return 0;
}

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