https://www.xkcd.com/blue_eyes.htmlThe island puzzle, for those who haven't seen it yet.
I think that one is much more difficult because the problem is stated in a way that makes the readers think she has much less information that is actually given. The birthday problem has no trick phrasing in it.
Well, maybe a little tricky. You'd get stuck if you tried to reason from four months and six days. This would be a likely mistake if the problem were read aloud with the list of dates as "May 15, 16, and 19, or June 17 and 18..."
Recognizing that Albert and Bernard are both working with sets of 10 elements each -- one for each possible date -- then it becomes a simple graph problem.
Write a chart with rows labeled months and columns labeled days. Put a mark on each possible date. Albert circles one row and Bernard one column. Albert says none of the marks in his rows are the only marks in their columns, so draw a line through the columns with only one mark and the rows that intersect at that mark. Bernard says there is only one mark in his column after eliminating the row, so draw a line through the columns with more than one mark. Albert says there is only one mark in his row, so draw a line through the row that still has two marks in it. The only one left is July 15.