#include <iostream>
using namespace std;
int ans1[6000010],v[3000010],r,n,ans2[6000010],ans,poz[3000010];
int main()
{
int t;
cin>>t;
++t;
while(--t)
{
int ver=0;
cin>>n;
for(int i=1;i<=n;++i)
{
cin>>v[i];
poz[v[i]]=i;
}
n/=2;
for(int i=1;i<=n;++i)
{
if(v[i]+v[2*n+1-i]!=2*n+1)
{
ver=1;
break;
}
if(v[i]>n)
++ver;
}
if(ver%2==1)
{
cout<<-1<<'\n';
continue;
}
ans=0;
ver=0;
for(int i=1;i<=n;++i)
{
while(v[i]!=i&&v[i]!=n*2-i+1)
{
++ans;
ans1[ans]=v[i];
ans2[ans]=i;
swap(poz[v[i]],poz[v[v[i]]]);
swap(poz[v[2*n-i+1]],poz[v[2*n-v[i]+1]]);
swap(v[2*n-i+1],v[2*n-v[i]+1]);
swap(v[i],v[v[i]]);
}
}
for(int i=1;i<=n;++i)
{
if(v[i]>n)
{
if(ver==0)
ver=i;
else
{
++ans;
ans1[ans]=ver;
ans2[ans]=2*n-i+1;
swap(v[i],v[2*n-ver+1]);
swap(v[ver],v[2*n-i+1]);
swap(poz[v[i]],poz[v[2*n-ver+1]]);
swap(poz[v[ver]],poz[v[2*n-i+1]]);
++ans;
ans1[ans]=ver;
ans2[ans]=i;
swap(v[i],v[ver]);
swap(v[2*n-ver+1],v[2*n-i+1]);
swap(poz[v[i]],poz[v[ver]]);
swap(poz[v[2*n-ver+1]],poz[v[2*n-i+1]]);
ver=0;
}
}
}
cout<<ans<<' '<<ans<<'\n';
for(int i=1;i<=ans;++i)
cout<<ans1[i]<<' '<<ans2[i]<<'\n';
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
332 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
46 ms |
560 KB |
Output is correct |
2 |
Correct |
43 ms |
420 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
332 KB |
Output is correct |
2 |
Correct |
46 ms |
560 KB |
Output is correct |
3 |
Correct |
43 ms |
420 KB |
Output is correct |
4 |
Correct |
42 ms |
568 KB |
Output is correct |
5 |
Correct |
15 ms |
380 KB |
Output is correct |
6 |
Correct |
16 ms |
420 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
46 ms |
560 KB |
Output is correct |
2 |
Correct |
43 ms |
420 KB |
Output is correct |
3 |
Correct |
860 ms |
10256 KB |
Output is correct |
4 |
Correct |
931 ms |
9832 KB |
Output is correct |
5 |
Correct |
857 ms |
11992 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
332 KB |
Output is correct |
2 |
Correct |
46 ms |
560 KB |
Output is correct |
3 |
Correct |
43 ms |
420 KB |
Output is correct |
4 |
Correct |
42 ms |
568 KB |
Output is correct |
5 |
Correct |
15 ms |
380 KB |
Output is correct |
6 |
Correct |
16 ms |
420 KB |
Output is correct |
7 |
Correct |
860 ms |
10256 KB |
Output is correct |
8 |
Correct |
931 ms |
9832 KB |
Output is correct |
9 |
Correct |
857 ms |
11992 KB |
Output is correct |
10 |
Correct |
825 ms |
9440 KB |
Output is correct |
11 |
Correct |
772 ms |
7728 KB |
Output is correct |
12 |
Correct |
826 ms |
10968 KB |
Output is correct |
13 |
Correct |
862 ms |
12372 KB |
Output is correct |
14 |
Correct |
860 ms |
10580 KB |
Output is correct |