Transform String (Google India)

Problem Overview

• Find the minimum number of operations to transform one string into another under adjacency rules.
• Input: two equal-length strings over {x, y, z}, each with no consecutive identical characters; Output: minimal operation count.
• Operation: change any single character, but the string must still have no adjacent equal characters after each change.
• Domain: string transformation/text processing; a Google India coding interview problem and interview question from Google interviews.