Suppose we have a list of numbers called nums, we will exchange each consecutive even indexes with each other, and also exchange each consecutive odd index with each other.
So, if the input is like [1,2,3,4,5,6,7,8,9], then the output will be [3, 4, 1, 2, 7, 8, 5, 6, 9]
To solve this, we will follow these steps −
- length := size of nums
- for i in range 0 to length, increase by 4, do
- if i+2<length, then
- exchange nums[i] and nums[i+2]
- if i+3<length, then
- exchange nums[i+1] and nums[i+3]
- if i+2<length, then
- return nums
Let us see the following implementation to get better understanding −
Example
class Solution: def solve(self, nums): length = len(nums) for i in range(0,length,4): if(i+2<length): nums[i], nums[i+2] = nums[i+2], nums[i] if(i+3<length): nums[i+1], nums[i+3] = nums[i+3], nums[i+1] return nums ob = Solution() nums = [1,2,3,4,5,6,7,8,9] print(ob.solve(nums))
Input
[1,2,3,4,5,6,7,8,9]
Output
[3, 4, 1, 2, 7, 8, 5, 6, 9]