C++ 代码
#include<bits/stdc++.h>
using namespace std;
int main()
{
int n,a[100000],t,sum = 0;
cin >> n;
for(int i=1;i<=n;i++)
cin >> a[i];
for(int i=1;i<=n;i++)
{
if(a[i] != i)
{
for(int j=i+1;j<=n;j++)
{
if(a[j] == i)
{
t = a[j];
a[j] = a[i];
a[i] = t;
sum++;
break;
}
}
}
}
cout << sum;
return 0;
}