Given a string str consisting of only characters ‘a’ and ‘b’, the task is to check whether the string is valid or not. In a valid string, every group of consecutive b must be of length 2 and must appear after 1 or more occurrences of character ‘a’ i.e. “abba” is a valid sub-string but “abbb” and aba are not. Print 1 if the string is valid else print -1.
Input: str = “abbaaabbabba”
Input: str = “abbaaababb”
Approach: Find every occurrence of ‘b’ in the string and check whether it is a part of the sub-string “abb”. If the condition fails for any sub-string then print -1 else print 1.
Below is the implementation of the above approach:
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