#include "bits/stdc++.h"
using namespace std;
const long long MX=2e5+10;
int a[MX];
int p[MX];
pair < int , int > vp1[MX];
pair < int , int > vp2[MX];
int n;
void swp(int i,int j) {
swap(a[i], a[j]);
swap(p[a[i]], p[a[j]]);
swap(a[n - i + 1], a[n - j + 1]);
swap(p[a[n - i + 1]], p[a[n - j + 1]]);
}
void fun() {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> a[i];
p[a[i]] = i;
}
for (int i = 1; i <= n / 2; i++) {
if (a[i] + a[n - i + 1] != (n + 1)) {
cout << "-1\n";
return;
}
}
int o1 = 0, o2 = 0;
for (int i = 1; i <= n / 2; i++) {
if (a[i] == i) {
continue;
}
if (a[i] == a[n - i + 1]) {
vp1[++o1] = make_pair(i, n - i + 1);
} else {
vp2[++o2] = make_pair(i, p[i]);
swp(i, p[i]);
}
}
if (o1 & 1) {
cout << "-1\n";
return;
}
while (o1) {
vp2[++o2] = make_pair(vp1[o1].first, vp1[o1 - 1].first);
vp2[++o2] = make_pair(vp1[o1].first, vp1[o1 - 1].second);
o1 -= 2;
}
cout << o2 << " " << o2 << "\n";
for (int i = 1; i <= o2; i++) {
cout << vp2[i].first << " " << vp2[i].second << "\n";
}
}
int main() {
cin.tie(0);
ios_base::sync_with_stdio(0);
int t;
cin >> t;
while (t--) {
fun();
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
2392 KB |
Wrong answer |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
15 ms |
2652 KB |
Output is correct |
2 |
Correct |
13 ms |
3164 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
2392 KB |
Wrong answer |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
15 ms |
2652 KB |
Output is correct |
2 |
Correct |
13 ms |
3164 KB |
Output is correct |
3 |
Correct |
320 ms |
31248 KB |
Output is correct |
4 |
Correct |
278 ms |
29776 KB |
Output is correct |
5 |
Correct |
320 ms |
31840 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
2392 KB |
Wrong answer |
2 |
Halted |
0 ms |
0 KB |
- |