PAT 1067 Sort with Swap(0,*)

#include <stdio.h>
#include <string.h>
#include <iostream>
using namespace std;
int n,right1,count;
int Father[100005];
int FindFather(int x){
if (Father[x]!=-1) {
Father[x]=FindFather(Father[x]);
return  Father[x];
}
else
return x;
}
void Union(int a,int b){
int tempa=FindFather(a);
int tempb=FindFather(b);
if (tempa!=tempb) {
Father[tempa]=tempb;
}
}
int main(){
int index,ringnum=0;
memset(Father,0xff,sizeof(Father));
//freopen("/Users/pantingting/Documents/code/data/input", "r", stdin);
scanf("%d",&n);
for (int i=0; i<n; i++) {
scanf("%d",&index);
if (index==i) {
Father[i]=-2;
right1++;
}
else
Union(index, i);
}
for (int i=0; i<n; i++) {
if (Father[i]==-1) {
ringnum++;
}
}
int ans=n-right1+ringnum;
if (Father[0]!=-2) {
ans-=2;
}
printf("%d\n",ans);
return 0;
}