#include "sorting.h"
#include<bits/stdc++.h>
using namespace std;
vector<pair<int,int>> solve(vector<int> v){
vector<bool> seen(v.size(), false);
vector<pair<int,int>> res;
for (int i=0; i<v.size(); i++){
if (seen[i]) continue;
seen[i] = true;
int j = i;
while (!seen[v[j]]){
res.push_back({i, v[i]});
j = v[j];
seen[j] = true;
}
}
return res;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]){
vector<int> f(N), g(N);
for (int i=0; i<N; i++){
f[i] = i;
g[i] = i;
}
int l = -1, r = M;
/*while (l != r-1){
int m = (l+r)/2;
vector<int> gx = g;
for (int i=0; i<m; i++) swap(gx[X[i]], gx[Y[i]]);
vector<int> v(N);
for (int i=0; i<N; i++) v[i] = S[gx[i]];
if (solve(v).size() <= m) r = m;
else l = m;
}*/
for (int i=0; i<r; i++){
swap(g[X[i]], g[Y[i]]);
swap(f[g[Y[i]]], f[g[X[i]]]);
}
vector<int> v(N);
for (int i=0; i<N; i++) v[i] = S[g[i]];
vector<pair<int,int>> res = solve(v);
if (res.size() < r) res.push_back({0, 0});
vector<int> s(N);
for (int i=0; i<N; i++) s[i] = S[i];
vector<int> s2 = s;
sort(s2.begin(), s2.end());
for (int i=0; i<res.size(); i++){
swap(f[X[i]], f[Y[i]]);
swap(g[f[Y[i]]], g[f[X[i]]]);
P[i] = g[res[i].first];
Q[i] = g[res[i].second];
swap(s[X[i]], s[Y[i]]);
swap(s[P[i]], s[Q[i]]);
if (s == s2) return i+1;
}
return res.size();
}
