Submission #579991

#	Time	Username	Problem	Language	Result	Execution time	Memory
579991		Mr_Husanboy	Xor Sort (eJOI20_xorsort)	C++14	100 / 100	11 ms	1104 KiB

xorsort

// Muallif: Mansuraliyev Husanboy Murotali o'g'li  >> NamPS

#include<bits/stdc++.h>

using namespace std;
#define ll long long
#define ios ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define all(a) a.begin(), a.end()
#define F first
#define S second

struct segtree{
	vector<int> t;
	int sz=0;
	void init(int n){
		t.assign(4*n+1,0);
		sz=n;
	}
	void upd(int x, int l, int r, int ind, int val){
		if(l==r){
			t[x]=val;return;
		}
		int m=(l+r)/2;
		if(ind>m){
			upd(x*2+1,m+1,r,ind,val);
		}else upd(x*2,l,m,ind,val);
		t[x]=t[x*2]^t[x*2+1];
	}
	void upd(int ind, int val){
		upd(1,1,sz,ind,val);
	}
	int get(int x, int l, int r, int lx, int rx){
		if(lx<=l&&r<=rx){
			return t[x];
		}
		if(r<lx||rx<l){
			return 0;
		}
		int m=(l+r)/2;
		return get(x*2,l,m,lx,rx)^get(x*2+1,m+1,r,lx,rx);
	}
	int get(int l,int r){
		return get(1,1,sz,l,r);
	}
};

segtree t;

void solve(){
	int n,s;
	cin>>n>>s;
	int a[n],b[n+1];
	t.init(n);
	for(int i=0;i<n;i++) cin>>a[i];
	for(int i=1;i<=n;i++) b[i]=a[i-1],t.upd(i,b[i]);
	vector<pair<int,int> > ans;
	int mx=1e9;
	if(s==1){//cout<<"doe"<<endl;
		for(int i=n;i>=1;i--){
			
			int mx2=0,ind=0;
			for(int j=1;j<=i;j++){
				int cur=t.get(j,i);
				if(cur>=mx) continue;
				if(cur>mx2) mx2=cur,ind=j;
			}//cout<<ind<<"\n";
			
			if(ind==0){
			//	cout<<"wrong solution";return;
				for(int j=i;j<n&&b[j]>b[j+1];j++){
					swap(b[j],b[j+1]);
					t.upd(j,b[j]); t.upd(j+1,b[j+1]);
					ans.push_back({j,j+1});
					ans.push_back({j+1,j});
					ans.push_back({j,j+1});
				}
				//cout<<i<<' ';
			}else for(int j=ind; j<i;j++){
				ans.push_back({j+1,j});
				b[j+1]^=b[j];
				t.upd(j+1,b[j+1]);
			}
			mx=b[i];
		}
		//for(int i=1;i<=n;i++) cout<<b[i]<<' ';cout<<endl;
		cout<<ans.size()<<"\n";
		for(auto u:ans){
			cout<<u.F<<' '<<u.S<<"\n";
		}
		return;
	}
	
	int done=0; bool ok=0;
	for(int i=19;i>=0;i--){
		ok=0;
		for(int j=0;j<n-done-1;j++){
			
			if(a[j]&(1<<i)){
				ok=1;
				if(a[j+1]&(1<<i)){
					ans.push_back({j,j+1});
					a[j]^=a[j+1];
				}else{
					ans.push_back({j+1,j});
					ans.push_back({j,j+1});
					a[j+1]^=a[j];
					a[j]^=a[j+1];
				}
			}
		}
		done+=ok;
	}
	cout<<ans.size()<<"\n";
	for(auto u:ans){
		cout<<u.F+1<<' '<<u.S+1<<"\n";
	}
}


int main(){
	ios;
	//int t=1;   cin>>t; while(t--)
	solve();
}

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