#include "sorting.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
#define ff first
#define ss second
#define pii pair<int,int>
#define vi vector<int>
const int N = 1e6+100, M = 1e5+10, K = 52, MX = 30;
int findSwapPairs(int n, int S[], int m, int X[], int Y[], int P[], int Q[]) {
int l = 0, r = m, ans = m;
while(l <= r){
int mid = l+r>>1;
vector<pii> SW;
vector<int> v, pos_val(n), pos_plate(n), plate(n), val(n);
for(int i = 1; i <= n; ++i) v.pb(i-1);
for(int i = 0; i < n; ++i) val[i] = S[i], pos_val[S[i]] = i;
for(int i = 0; i < mid; ++i){
swap(val[X[i]], val[Y[i]]);
}
for(int i = 0; i < n; ++i){
plate[pos_val[val[i]]] = i;
}
for(int i = 0; i < n; ++i) val[i] = S[i], pos_val[S[i]] = i;
for(int i = 0; i < n; ++i) pos_plate[plate[i]] = i;
// cerr << mid << " plate\n";
// for(int x: plate) cerr << x << ' ';
// cerr << '\n';
for(int i = 0; i < mid; ++i){
swap(val[X[i]], val[Y[i]]);
swap(pos_val[val[X[i]]], pos_val[val[Y[i]]]);
swap(plate[X[i]], plate[Y[i]]);
swap(pos_plate[plate[X[i]]], pos_plate[plate[Y[i]]]);
while(v.size() && pos_plate[v.back()] == pos_val[v.back()]){
v.pop_back();
}
if(v.empty()){
SW.pb({0, 0}); // no swap
}else{
int vall = v.back();
v.pop_back();
int x = pos_plate[vall];
int y = pos_val[vall];
SW.pb({x, y});
swap(val[x], val[y]);
swap(pos_val[val[x]], pos_val[val[y]]);
// swap(plate[x], plate[y]);
// swap(pos_plate[plate[x]], pos_plate[plate[y]]);
}
// cerr << "after " << i << '\n';
// for(int x: val) cerr << x << ' '; cerr << '\n';
// for(int x: plate) cerr << x << ' '; cerr << '\n';
// cerr << '\n';
}
// cerr << mid << '\n';
// for(int x: plate) cerr << x << ' ';
// cerr << '\n';
bool ok = 1;
for(int i = 1; i < n; ++i) ok = ok & (val[i] > val[i - 1]);
if(ok){
ans = mid;
r = mid - 1;
for(int i = 0; i < mid; ++i) P[i] = SW[i].ff, Q[i] = SW[i].ss;
}else{
l = mid + 1;
}
}
return ans;
}
