Submission #464090

#	Time	Username	Problem	Language	Result	Execution time	Memory
464090		amunduzbaev	Xor Sort (eJOI20_xorsort)	C++14	60 / 100	196 ms	15920 KiB

xorsort

#include "bits/stdc++.h"
using namespace std;

void solve(){
	int s, n; cin>>n>>s;
	vector<int> a(n);
	for(auto& x : a) cin>>x;
	
	vector<array<int, 2>> mx, rr;
	for(int i=0;i<n;i++){
		mx.push_back({a[i], i});
	} sort(mx.rbegin(), mx.rend());
	
	for(int i=0;i<(int)mx.size();i++){
		int p = mx[i][1];
		
		for(int i=0;i+1<n;i++){
			a[i] ^= a[i+1];
			rr.push_back({i, i+1});
		}
		
		if(i) n--;
		
		for(int i=p;i+1<n;i++){
			a[i+1] ^= a[i];
			rr.push_back({i+1, i});
		}
		
		for(int i=p-2;i>=0;i--){
			a[i] ^= a[i+1];
			rr.push_back({i, i+1});
		}
		
		assert(a[n - 1] == mx[i][0]);
		for(int j=i + 1;j<(int)mx.size();j++){
			if(mx[j][1] > p) mx[j][1]--;
		}
		//~ for(int i=0;i<(int)a.size();i++) cout<<a[i]<<" ";
		//~ cout<<"\n";
	}
	
	cout<<(int)rr.size()<<"\n";
	for(auto x : rr) cout<<x[0] + 1<<" "<<x[1] + 1<<"\n";
}

/*

5 1
3 2 8 4 1

*/

signed main(){
	ios_base::sync_with_stdio(0); cin.tie(0);
	int t = 1;
	//~ cin>>t;
	while(t--) solve();
}

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