Reverse, Rotate & Manipulate Arrays in Java | Animated DSA #10

Array Manipulation in Java, explained with animated examples and worked code. Reverse, rotate, inverse — and the enumeration templates for subarrays and subsets Lesson 10 of It’s Leo’s rebuilt DSA course. Practice alongside the examples and check the reasoning before moving on. CHAPTERS 00:00:00 Array manipulation starts with a precise contract 00:00:51 Reversal fixes a pair of final positions at each step 00:01:40 The reversal invariant describes the unfinished window 00:02:31 Normalize a rotation only after handling an empty array 00:03:25 Three reversals transform a right rotation 00:04:11 The block proof explains why the three calls work 00:05:02 A copy-based rotation is a useful independent oracle 00:05:57 A permutation inverse maps each value back to its index 00:06:49 Validate the permutation before promising an inverse 00:07:44 Contiguous slices and ordered selections are different 00:08:38 Counts depend on empty-output and duplicate conventions 00:09:35 Enumerating boundaries costs less than copying every slice 00:10:29 A bitmask chooses positions; its width needs a contract 00:11:30 Floor and ceiling should represent absence explicitly 00:12:34 Test the algebra as well as individual examples 00:13:31 Practice by changing one contract at a time #DSA #Java #Algorithms