Given any permutation of the numbers {0, 1, 2,..., N-1}, it is easy to sort them in increasing order. But what if Swap(0, *) is the ONLY operation that is allowed to use? For example, to sort {4, 0, 2, 1, 3} we may apply the swap operations in the following way:
Swap(0, 1) => {4, 1, 2, 0, 3}
Swap(0, 3) => {4, 1, 2, 3, 0}
Swap(0, 4) => {0, 1, 2, 3, 4}
Now you are asked to find the minimum number of swaps need to sort the given permutation of the first N nonnegative integers.
Input Specification:
Each input file contains one test case, which gives a positive N (<=105) followed by a permutation sequence of {0, 1, ..., N-1}. All the numbers in a line are separated by a space.
Output Specification:
For each case, simply print in a line the minimum number of swaps need to sort the given permutation.
Sample Input:
10 3 5 7 2 6 4 9 0 8 1
Sample Output:
9
#include <stdio.h>
#include<algorithm>
using namespace std;
int main()
{
int n;
int loc[];
while(scanf("%d",&n)!=EOF)
{ int tem,i,left;
left = n-;
for(i=;i<n;i++)
{
scanf("%d",&tem);
loc[tem] = i;
if(tem == i && i!=)
--left;
} int count = ;
int k = ;
while(left > )
{
if(loc[]==)
{
while(k < n)
{
if( loc[k] != k )
{
swap(loc[],loc[k]);
++count;
break;
}
++k;
}
} while(loc[]!=)
{
swap(loc[],loc[loc[]]);
++count;
--left;
} } printf("%d\n",count);
}
return ;
}