#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int INF=1e9;
const ll LINF=1e18;
#define fi first
#define se second
#define pii pair<int,int>
#define mid ((l+r)/2)
#define sz(a) (int((a).size()))
#define all(a) a.begin(),a.end()
#define endl "\n"
#define PRINT(x) cerr<<#x<<'='<<x<<endl;
#define pb push_back
#define PRINTvec(niz) { cerr<<#niz<<"="; for(auto _i:niz) cerr<<_i<<" "; cerr<<endl; }
void Solve(){
int N,S; cin>>N>>S;
bool subtask1=(2<=N && N<=150 && S==1);
bool subtask2=(2<=N && N<=200 && S==1);
bool subtask3=(2<=N && N<=1000 && S==2);
vector<int> a(N+1); for(int i=1;i<=N;i++) cin>>a[i];
vector<pii> opers;
function<void(int,int)> Oper=[&](int i,int j){
if(abs(i-j)==1) a[i]=a[i]^a[j];
opers.pb({i,j});
};
function<bool(int,int)> Has=[&](int x,int bit){
return (x&(1<<bit))>0;
};
if(subtask1){
for(int i=1;i<=N;i++){
for(int j=1;j<=N-1;j++){
if(a[j]>a[j+1]){
Oper(j,j+1);
Oper(j+1,j);
Oper(j,j+1);
}
}
}
}
else if(subtask2){
}
else if(subtask3){
set<int> s;
function<void(int,int,int)> Update=[&](int i,int j,int bit){
if(!Has(a[i],bit) && s.count(i)) s.erase(i);
if(!Has(a[j],bit) && s.count(j)) s.erase(j);
if(Has(a[i],bit)) s.insert(i);
if(Has(a[j],bit)) s.insert(j);
};
for(int bit=20;bit>=0;bit--){
s.clear();
bool pomeren=false;
for(int i=L;i<=R;i++){
if(Has(a[i],bit)){
s.insert(i);
pomeren=true;
}
}
while(!s.empty() && !(sz(s)==1 && s.count(R))){
int i=*(s.begin());
if(Has(a[i+1],bit)){
Oper(i,i+1); Update(i,i+1,bit);
}
else{
Oper(i+1,i); Update(i,i+1,bit);
Oper(i,i+1); Update(i,i+1,bit);
}
}
if(pomeren) --R;
}
}
cout<<sz(opers)<<endl;
for(auto p:opers) cout<<p.fi<<" "<<p.se<<endl;
PRINTvec(a);
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t;
//cin>>t;
t=1;
while(t--){
Solve();
}
return 0;
}
Compilation message
xorsort.cpp: In function 'void Solve()':
xorsort.cpp:61:23: error: 'L' was not declared in this scope
61 | for(int i=L;i<=R;i++){
| ^
xorsort.cpp:61:28: error: 'R' was not declared in this scope
61 | for(int i=L;i<=R;i++){
| ^
xorsort.cpp:67:55: error: 'R' was not declared in this scope
67 | while(!s.empty() && !(sz(s)==1 && s.count(R))){
| ^
xorsort.cpp:77:27: error: 'R' was not declared in this scope
77 | if(pomeren) --R;
| ^
