Hackerrank - Alternating Characters Solution
You are given a string containing characters and only. Your task is to change it into a string such that there are no matching adjacent characters. To do this, you are allowed to delete zero or more characters in the string.
Your task is to find the minimum number of required deletions.
For example, given the string , remove an at positions and to make in deletions.
Complete the alternatingCharacters function in the editor below. It must return an integer representing the minimum number of deletions to make the alternating string.
alternatingCharacters has the following parameter(s):
- s: a string
The first line contains an integer , the number of queries.
The next lines each contain a string .
- Each string will consist only of characters and
For each query, print the minimum number of deletions required on a new line.
5 AAAA BBBBB ABABABAB BABABA AAABBB
3 4 0 0 4
The characters marked red are the ones that can be deleted so that the string doesn't have matching consecutive characters.
Solution in Python
def alternatingCharacters(s): a,b = "", "" for i in s: if b!=i: a+=i b=i return len(s)-len(a) for _ in range(int(input())): print(alternatingCharacters(input()))
import re def alternatingCharacters(s): return len(s)-len(re.sub(r"([AB])\1+",lambda x: x.groups(), s)) for _ in range(int(input())): print(alternatingCharacters(input()))