Given a non-empty string of lowercase ASCII letters
a-z, output that string with each consecutive “run” of the same letter lengthened by one more copy of that letter.
g’s) turns into
This is code-golf: the shortest answer in bytes wins.
aabbcccc -> aaabbbccccc doorbell -> ddooorrbbeelll uuuuuuuuuz -> uuuuuuuuuuzz q -> qq xyxyxy -> xxyyxxyyxxyy xxxyyy -> xxxxyyyy