Submission #1070294

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070294		AdamGS	Xor Sort (eJOI20_xorsort)	C++17	100 / 100	7 ms	1100 KiB

xorsort

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=1e3+7;
int T[LIM], n;
vector<pair<int,int>>V;
void solve1() {
	rep(i, n-1) V.pb({i+1, i});
	rep(i, n) for(int j=i; j>0; --j) if(T[j-1]>T[j]) {
		V.pb({j-1, j});
		if(j-1>0) V.pb({j-1, j-2});
		swap(T[j], T[j-1]);
	}
	for(int i=n-2; i>=0; --i) V.pb({i+1, i});
}
void solve2() {
	for(int i=19; i>=0; --i) {
		rep(j, n-1) {
			if(T[j+1]>=(1<<(i+1))) break;
			if(!(T[j]&(1<<i))) continue;
			if(!(T[j+1]&(1<<i))) {
				V.pb({j+1, j});
				T[j+1]^=T[j];
			}
			V.pb({j, j+1});
			T[j]^=T[j+1];
		}
	}
}
int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	int s;
	cin >> n >> s;
	rep(i, n) cin >> T[i];
	if(s==1) solve1();
	else solve2();
	cout << V.size() << '\n';
	for(auto i : V) cout << i.st+1 << " " << i.nd+1 << '\n';
}

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