#include <bits/stdc++.h>
using namespace std;
vector<pair<int,int>> con;
bool vis[200001];int arr[200001];
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);
int t;cin>>t;
z:while(t--){
int n;cin>>n;
for(int i = 1;i<=n;i++)vis[i] = 0;
con.clear();
int pos[n+1];
for(int i = 1;i<=n;i++){
cin>>arr[i];pos[arr[i]] = i;
}
int g = 0;int lol = 0;
for(int i = 1;i<=n/2;i++){
if(arr[i]!=i)g++;
if(n-arr[i]+1!=arr[n-i+1]){
cout<<-1<<endl;
goto z;
}if(arr[i]>n/2){
lol++;
}
}
if(lol&1){
cout<<-1<<endl;
goto z;
}
for(int i = 1;i<=n;i++){
while(pos[i]!=i&&pos[i]!=n-i+1) {
int tmp=pos[i];
con.push_back({i,tmp});
swap(pos[i],pos[tmp]);
swap(pos[n-i+1],pos[n-tmp+1]);
}
}
cout<<con.size()<<" "<<con.size()<<"\n";
for(auto i:con)cout<<i.first<<" "<<i.second<<"\n";
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
344 KB |
Correctly distinguished between possibility and impossibility |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
14 ms |
600 KB |
Correct number of moves |
2 |
Correct |
14 ms |
600 KB |
Correct number of moves |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
344 KB |
Correctly distinguished between possibility and impossibility |
2 |
Correct |
14 ms |
600 KB |
Correct number of moves |
3 |
Correct |
14 ms |
600 KB |
Correct number of moves |
4 |
Correct |
14 ms |
600 KB |
Correctly distinguished between possibility and impossibility |
5 |
Correct |
5 ms |
348 KB |
Correctly distinguished between possibility and impossibility |
6 |
Correct |
6 ms |
348 KB |
Correctly distinguished between possibility and impossibility |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
14 ms |
600 KB |
Correct number of moves |
2 |
Correct |
14 ms |
600 KB |
Correct number of moves |
3 |
Correct |
286 ms |
10544 KB |
Correct number of moves |
4 |
Correct |
284 ms |
10184 KB |
Correct number of moves |
5 |
Correct |
296 ms |
12508 KB |
Correct number of moves |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
344 KB |
Correctly distinguished between possibility and impossibility |
2 |
Correct |
14 ms |
600 KB |
Correct number of moves |
3 |
Correct |
14 ms |
600 KB |
Correct number of moves |
4 |
Correct |
14 ms |
600 KB |
Correctly distinguished between possibility and impossibility |
5 |
Correct |
5 ms |
348 KB |
Correctly distinguished between possibility and impossibility |
6 |
Correct |
6 ms |
348 KB |
Correctly distinguished between possibility and impossibility |
7 |
Correct |
286 ms |
10544 KB |
Correct number of moves |
8 |
Correct |
284 ms |
10184 KB |
Correct number of moves |
9 |
Correct |
296 ms |
12508 KB |
Correct number of moves |
10 |
Correct |
288 ms |
9492 KB |
Correctly distinguished between possibility and impossibility |
11 |
Correct |
248 ms |
7784 KB |
Correctly distinguished between possibility and impossibility |
12 |
Correct |
274 ms |
11032 KB |
Correctly distinguished between possibility and impossibility |
13 |
Correct |
291 ms |
12388 KB |
Correctly distinguished between possibility and impossibility |
14 |
Correct |
266 ms |
10776 KB |
Correctly distinguished between possibility and impossibility |