765F and 1793F from a week ago.

1771B and 652C. They are basically the same task but the permutation is $$$\left[1,2,3,...,n-1,n\right]$$$ in 1771B while it can be any permutation in 652C

This 1790F - Timofey and Black-White Tree and 342E - Xenia and Tree overall still pretty interesting problem

1141E - Superhero Battle and 1490G - Old Floppy Drive they are both from Div 3 contests, one has multiple testcases while the other doesn't.

1795C in educational round same as 923B

All the problems until 2000 rating that involve the concept of permutation groups , permutation parity and permutation cycles are similar;

407B and 1552F. The latter is just the former with a ton of shit added on top.

1462C - Unique Number and 1714C - Minimum Varied Number are the same, except the constraints (45 vs 50)

713C - Sonya and Problem Wihtout a Legend and 13C - Sequence

Differences: strictly increasing/non-decreasing, N=3000/5000. In other words, no difference...