#include "sorting.h" #include<bits/stdc++.h> using namespace std; #define maxn 2005 int n, s[maxn]; int a[maxn], pos[maxn]; pair<int,int> sw[maxn]; int get(int rec) { int i,x,cnt; for(i=0;i<n;i++) a[i] = s[i]; for(i=0;i<n;i++) pos[a[i]] = i; cnt = 0; for(i=0;i<n;i++) { x = pos[i]; if(i!=x) { pos[a[i]] = x; swap(a[i], a[x]); if(rec) sw[cnt] = {a[i],a[x]}; cnt++; } } return cnt; } int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) { int i,x,now; n = N; for(i=0;i<n;i++) s[i] = S[i]; for(now=-1;now<M;now++) { if(now>=0) swap(s[X[now]],s[Y[now]]); if(get(0)<=now+1) break; } get(1); for(i=0;i<n;i++) s[i] = S[i]; for(i=0;i<now+1;i++) { swap(s[X[i]], s[Y[i]]); // printf("i = %d : {%d, %d}\n",i,sw[i].first,sw[i].second); for(x=0;x<n;x++) { if(s[x]==sw[i].first) P[i] = x; if(s[x]==sw[i].second) Q[i] = x; } swap(s[P[i]], s[Q[i]]); } return now+1; }