Selection sort

Question

Can anybody explain me why the number of swaps in selection sort algorithm is  (n-1) in worst case ?

Let's say the array is {6,5,4,3,2,1} then the number of swaps should be 5. But I think the no of swaps should be 3.

Please explain.

Comments

{3,4,6,5,1,2} - check this

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Is there any formula to calculate number of swaps in selection sort algo??

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@Akshay0798 n-1 :)

Answer 1

Basic selection sort procedure works as follow:

1. Find ith minimum from the array.
2. Place it at ith position.

Even if you have the ith minimum at ith position already, we do a swap, so n-1 swaps for all permutations.