Replace By X

1. Given a string and a pattern. 
 2. Replace all the continuous occurrence of pattern with a single X in the string.

1 <= size of str,s <= 1000

Try First, Check Solution later

1. You should first read the question and watch the question video.
2. Think of a solution approach, then try and submit the question on editor tab.
3. We strongly advise you to watch the solution video for prescribed approach.

abababcdefababcdab
ab

XcdefXcdX