Submission #372889

#	Time	Username	Problem	Language	Result	Execution time	Memory
372889		Traduttore	Xor Sort (eJOI20_xorsort)	C++14	60 / 100	1095 ms	24756 KiB

xorsort

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define pll pair <ll,ll>
#define F first
#define S second
#define int ll
#define pb push_back
#define IOS ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
using namespace std;
using namespace __gnu_pbds;
typedef tree <pll,null_type,less <pll>,rb_tree_tag,tree_order_statistics_node_update> orduk;
typedef tree <ll,null_type,less <ll>,rb_tree_tag,tree_order_statistics_node_update> orduk2;
ll n,type;
vector <ll> a;
inline void init() {
    cin>>n>>type;
    a.resize(n);
    for (int i = 0;i < n;i++)
        cin>>a[i];
}
vector <pll> ans;
inline void output() {
    cout<<ans.size()<<'\n';
    for (auto to:ans)
        cout<<to.F<<" "<<to.S<<'\n';
    exit(0);
}
inline void solve() {
	int mn = 2e9;
	vector <pll> ans2;
	for (int i = 0;i < n - 1;i++)
	a[i]^=a[i + 1];
	for (int j = 0;j < n;j++) {
		vector <int> aa;
		aa = a;
	for (int i = 0;i < n;i++)
	if (i != j) a[i]^=a[j];
	ans.clear();
	vector <int> ab;
	ab = aa;
	for (int i = 0;i < n - 1;i++)
	ans.pb({i + 1,i + 2});
	for (int i = j + 1;i < n;i++)
	{
		ans.pb({i + 1,i});
		ab[i]^=ab[i - 1];
	}
	for (int i = j - 1;i >= 0;i--)
	{
		ans.pb({i + 1,i + 2});
		ab[i]^=ab[i + 1];
	}
	a = ab;
	unordered_map <int,int> mp;
	bool YY = true;
	for (int i = 0;i < n;i++)
	{
		if (mp[a[i]]) {YY = false;break;}
		++mp[a[i]];
	}
	if (YY == false) {
		a = aa;
		continue;
	}
    while (1) {
        bool found = true;
        int mx = -1;
        int pos = -1;
        for (int i = 0;i < n - 1;i++)
        if (a[i] > a[i + 1]) {
        	pos = i;
        	break;
        }
        if (pos < 0) break;
            ans.pb({pos + 2,pos + 1});
            ans.pb({pos + 1, pos + 2});
            ans.pb({pos + 2,pos + 1});
            swap(a[pos],a[pos + 1]);
    }
    if (ans.size() < mn) {
    	mn = ans.size();
    	ans2 = ans;
    }
    a = aa;
}
ans = ans2;
}

int32_t main() {
//freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
IOS;
int m;
m = 10;
m-=9;
while (m--)
{
    init();
    solve();
    output();
}
}
/*written by Traduttore*/
/*waiting for a miracle...*/

Compilation message (stderr)

xorsort.cpp: In function 'void solve()':
xorsort.cpp:69:14: warning: unused variable 'found' [-Wunused-variable]
   69 |         bool found = true;
      |              ^~~~~
xorsort.cpp:70:13: warning: unused variable 'mx' [-Wunused-variable]
   70 |         int mx = -1;
      |             ^~
xorsort.cpp:83:20: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   83 |     if (ans.size() < mn) {
      |         ~~~~~~~~~~~^~~~

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