I need this question to be solved on Python language please..

Given a list of N characters of 'A' and 'B', where the characters are randomly ordered. It is permitted to replace (not swap) any element 'A' by 'B' and vice versa in order to guarantee that there is no any two similar consecutive characters. It is requested to develop an algorithm to do this task with the minimum number of replacements. For example:

Input: [A, B, A, A, B, A, A]

Output: minimum replacements = 3 --> [A, B, A, B, A, B, A]

a) Develop your algorithm to do the task with the minimum number of replacement. [Note: you have to explain how your algorithm will work]

b) Analyze its complexity and explain your answer.

c) To which type of problems does this problem belong: P, NP, NP-Hard, NP-Complete? Why?