Removing Stars From a String - Solution & Explanation

This approach utilizes a stack data structure to handle the character removals efficiently. As we iterate through the string, whenever a star (*) is encountered, we pop from the stack, effectively removing the last non-star character added. This allows us to handle both the star and its preceding non-star character in O(1) time.

The C implementation uses a character array as a stack to store non-star characters. We increment the top index when adding a character and decrement it when encountering a star, which effectively removes the most recent non-star character.

This alternative method involves using a simple two-pointer technique where we iterate through the string and build the result in place. We treat the string as a writable array and maintain a 'write' index that tells us where to place the next character. When we encounter a star, we just need to move the 'write' index back to overwrite the previous character.

This C implementation makes use of two indices: read, which traverses the string, and write, which indicates where to write the next character.