#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using lld = long double;
using ii = pair<int,int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
using vii = vector<ii>;
using vpll = vector<pll>;
using vlld = vector<lld>;
#define all(x) x.begin(),x.end()
#define lsb(x) x&(-x)
#define gcd(a,b) __gcd(a,b)
#define sz(x) (int)x.size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fls cout.flush()
#define fore(i, l, r) for (auto i = l; i < r; i++)
#define fo(i, n) fore (i, 0, n)
#define forex(i, r, l) for (auto i = r-1; i >= l; i--)
#define ffo(i, n) forex (i, n, 0)
bool cmin(ll &a, ll b) { if (b < a) { a=b; return 1; } return 0; }
bool cmax(ll &a, ll b) { if (b > a) { a=b; return 1; } return 0; }
void make_swap (ll i, ll j, vector<int> &a, vector<int> &pos) {
swap(a[i], a[j]);
swap(pos[a[i]], pos[a[j]]);
// for (ll i: a) cout << i << ' ';
// cout << '\n';
}
int findSwapPairs(int n, int A[], int M, int X[], int Y[], int P[], int Q[]) {
vector<int> a(n), pos(n);
fo (i, n) a[i] = A[i];
if (is_sorted(all(a))) return 0ll;
make_swap(0, 1, a, pos);
ll R = 0;
fo (i, n) pos[a[i]] = i;
if (pos[0] > 1) {
P[R] = 0;
Q[R] = pos[0];
R++;
make_swap(0, pos[0], a, pos);
if (is_sorted(all(a))) return R;
make_swap(0, 1, a, pos);
}
if (pos[1] > 1) {
ll f = (a[1] == 0 ? 0 : 1);
P[R] = f;
Q[R] = pos[1];
R++;
make_swap(f, pos[1], a, pos);
if (is_sorted(all(a))) return R;
make_swap(0, 1, a, pos);
}
assert(pos[0] <= 1);
assert(pos[1] <= 1);
assert(a[0]+a[1]==1);
while (!is_sorted(a.begin()+2, a.end())) {
fore (i, 2, n) {
if (a[i] != i) {
P[R] = i;
Q[R] = a[i];
make_swap(i, a[i], a, pos);
R++;
if (is_sorted(all(a))) return R;
make_swap(0, 1, a, pos);
break;
}
}
}
if (!is_sorted(all(a))) {
P[R] = 0;
Q[R] = 1;
make_swap(0, 1, a, pos);
R++;
}
assert(is_sorted(all(a)));
return R;
}
