#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5;
int p[MAXN];
int findSwapPairs(int n, int P[], int m, int hisX[], int hisY[], int myX[], int myY[]) {
int l = 0, r = m; int ans = 0;
while (l <= r) {
int mid = (l + r) / 2;
for (int i=0; i<n; i++) p[i] = P[i];
for (int i=0; i<mid; i++) swap(p[hisX[i]], p[hisY[i]]);
vector<pair<int, int>> ops(mid, make_pair(0, 0));
vector<bool> mark(n, false);
int swaps = 0; bool check = true;
for (int i=0; i<n; i++) {
if (mark[i]) continue;
vector<int> cycle;
int j = i;
// cerr << "cycle:";
while (!mark[j]) {
mark[j] = true;
cycle.push_back(j);
// cerr << j << ' ';
j = p[j];
}
// cerr << '\n';
for (j=1; j<(int)cycle.size(); j++) {
if (swaps >= mid) {
check = false;
break;
}
ops[swaps++] = {cycle[0], cycle[j]};
}
}
// cerr << mid << ':' << check << endl;
if (check) {
r = mid-1;
for (int op=0; op<mid; op++) {
myX[op] = ops[op].first;
myY[op] = ops[op].second;
}
ans = mid;
} else l = mid+1;
}
return ans;
}
