#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pi pair<int, int>
#define pl pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(),(x).end()
bool check(int n, int s[], int r, int x[], int y[], int p[], int q[]) {
for (int i=0; i<r; i++) {
swap(s[x[i]],s[y[i]]);
swap(s[p[i]],s[q[i]]);
}
bool ok=1;
for (int i=0; i<n; i++) {
ok&=(s[i]==i);
}
return ok;
}
int findSwapPairs(int n, int s[], int m, int x[], int y[], int p[], int q[]) {
int ss[n];
for (int i=0; i<n; i++) {
ss[i]=s[i];
}
int ind=0;
for (int i=0; i<n-1; i++) {
swap(s[x[ind]],s[y[ind]]);
p[ind]=i;
q[ind]=find(s,s+n,i)-s;
if (ind==1) {
p[ind]=0;
}
swap(s[p[ind]],s[q[ind]]);
if (p[ind]!=q[ind]) {
ind++;
}
else {
swap(s[x[ind]],s[y[ind]]);
}
}
if (s[0]!=0) {
p[ind]=0;
q[ind]=0;
ind++;
}
assert(check(n,ss,ind,x,y,p,q));
return ind;
}
