# Program to find number of swaps required to sort the sequence in python

Suppose we have a list of distinct numbers; we have to find the minimum number of swaps required to sort the list in increasing order.

So, if the input is like nums = [3, 1, 7, 5], then the output will be 2, as we can swap 3 and 1, then 5 and 7.

To solve this, we will follow these steps:

• sort_seq := sort the list nums
• table := a new map
• for each index i and value n in nums, do
• table[n] := i
• swaps := 0
• for i in range 0 to size of nums, do
• n := nums[i]
• s_n := sort_seq[i]
• s_i := table[s_n]
• if s_n is not same as n, then
• swaps := swaps + 1
• nums[s_i] := n
• nums[i] := s_n
• table[n] := s_i
• table[s_n] := i
• return swaps

Let us see the following implementation to get better understanding:

## Example Code

Live Demo

class Solution:
def solve(self, nums):
sort_seq = sorted(nums)
table = {}

for i, n in enumerate(nums):
table[n] = i
swaps = 0
for i in range(len(nums)):
n = nums[i]
s_n = sort_seq[i]
s_i = table[s_n]

if s_n != n:
swaps += 1
nums[s_i] = n
nums[i] = s_n
table[n] = s_i
table[s_n] = i

return swaps

ob = Solution()
nums = [3, 1, 7, 5]
print(ob.solve(nums))

## Input

[3, 1, 7, 5]

## Output

2