#include "bits/stdc++.h"
using namespace std;
#define ar array
typedef long long ll;
void solve(){
int n; cin>>n;
vector<int> a(n);
for(int i=0;i<n;i++) cin>>a[i];
vector<int> pos(n);
for(int i=0;i<n;i++) pos[--a[i]] = i;
vector<ar<int, 2>> res;
auto add = [&](int i, int j){
int i_ = n - i - 1, j_ = n - j - 1;
assert(j != i_);
swap(a[i], a[j]);
swap(pos[a[i]], pos[a[j]]);
res.push_back({i, j});
swap(a[i_], a[j_]);
swap(pos[a[i_]], pos[a[j_]]);
};
for(int i=0;i<n/2;i++){
if(a[i] == i) continue;
int j = pos[i];
if(j < n/2){
add(i, j);
} else {
if(n - j - 1 < i){
cout<<-1<<"\n";
return;
}
if(n - j - 1 == i){
if(i + 1 == j){
cout<<-1<<"\n";
return;
}
add(i, i + 1);
add(i, pos[i]);
} else {
add(i, j);
}
}
}
for(int i=1;i<n;i++){
if(a[i] < a[i-1]){
cout<<-1<<"\n";
return;
}
}
cout<<(int)res.size()<<" "<<(int)res.size()<<"\n";
for(auto x : res) cout<<x[0] + 1<<" "<<x[1] + 1<<"\n";
}
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
int t; cin>>t;
while(t--){
solve();
}
}
/*
10
4 9 6 3 1 ' 10 8 5 2 7
1 9 6 3 4 ' 7 8 5 2 10
1 2 3 4 5 ' 6 7 8 9 10
6
2 6 4 ' 3 1 5
1 2 3 ' 4 5 6
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
5 ms |
332 KB |
Valid reconstruction |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
24 ms |
544 KB |
Output is correct |
2 |
Correct |
18 ms |
956 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
5 ms |
332 KB |
Valid reconstruction |
2 |
Correct |
24 ms |
544 KB |
Output is correct |
3 |
Correct |
18 ms |
956 KB |
Output is correct |
4 |
Partially correct |
22 ms |
1092 KB |
Valid reconstruction |
5 |
Partially correct |
9 ms |
652 KB |
Valid reconstruction |
6 |
Partially correct |
7 ms |
460 KB |
Valid reconstruction |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
24 ms |
544 KB |
Output is correct |
2 |
Correct |
18 ms |
956 KB |
Output is correct |
3 |
Correct |
438 ms |
27700 KB |
Output is correct |
4 |
Correct |
421 ms |
25464 KB |
Output is correct |
5 |
Correct |
448 ms |
28440 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
5 ms |
332 KB |
Valid reconstruction |
2 |
Correct |
24 ms |
544 KB |
Output is correct |
3 |
Correct |
18 ms |
956 KB |
Output is correct |
4 |
Partially correct |
22 ms |
1092 KB |
Valid reconstruction |
5 |
Partially correct |
9 ms |
652 KB |
Valid reconstruction |
6 |
Partially correct |
7 ms |
460 KB |
Valid reconstruction |
7 |
Correct |
438 ms |
27700 KB |
Output is correct |
8 |
Correct |
421 ms |
25464 KB |
Output is correct |
9 |
Correct |
448 ms |
28440 KB |
Output is correct |
10 |
Partially correct |
422 ms |
25036 KB |
Valid reconstruction |
11 |
Partially correct |
427 ms |
23440 KB |
Valid reconstruction |
12 |
Partially correct |
454 ms |
27376 KB |
Valid reconstruction |
13 |
Partially correct |
449 ms |
28488 KB |
Valid reconstruction |
14 |
Partially correct |
440 ms |
26784 KB |
Valid reconstruction |