OLL 49
The algorithm, how to recognise it and how to practise it without cheating.
Recommended algorithm
r U' r2 U r2 U r2 U' r9 moves
How to recognise it
Only the back and right edges are yellow on top. A full yellow bar on the left, and the front-right corner's yellow faces you.
Its inverse is another case
Do the 49 algorithm backwards, r' U r2 U' r2 U' r2 U r', and you are solving 50.
That's why CubeDojo never scrambles 49 that way: it builds a random state with the case fixed, so you practise 49 and not 50.
Practise 49 now
Random-state scrambles, a timer and spaced review. Free, on the web and on your phone.