Computer Science Study guides, Class notes & Summaries

Create a spiral in matrix as shown in the figures on the first (visibile) page of the document

Van Eck's sequence in Matlab In recreational mathematics van Eck's sequence is an integer sequence defined recursively as follows. Let a0 = 0. Then, for n ≥ 0, if there exists an m < n such that am = an, take the largest such m and set an 1 = n − m; otherwise an 1 = 0. Thus the first occurrence of an integer in the sequence is followed by a 0, and the second and subsequent occurrences are followed by the size of the gap between the two most recent occurrences.

Problem 45. Make a Palindrome Number Created by Cody Team in Cody Challenge Some numbers like 323 are palindromes. Other numbers like 124 are not. But look what happens when we add that number to a reversed copy of itself. 124 421 ---- 545 Let's try another. 150 051 ---- 201 No, that didn't work, but what if we keep going? 201 102 ---- 303 There, it became a palindrome again. Given a, return b = find_palindrome(a) such that b is the palindrome numb...

Problem 44. Trimming Spaces Created by Cody Team in Cody Challenge Given a string, remove all leading and trailing spaces (where space is defined as ASCII 32). Input a = ' singular value decomposition ' Output b is 'singular value decomposition'

Problem 38. Return a list sorted by number of occurrences Created by Cody Team in Cody Challenge Given a vector x, return a vector y of the unique values in x sorted by the number of occurrences in x. Ties are resolved by a sort from lowest to highest. So if x = [1 2 2 2 3 3 7 7 93] then y = [2 3 7 1 93]

Problem 128. Sorted highest to lowest? Created by AMITAVA BISWAS in Community Return 1 if the input is sorted from highest to lowest, 0 if not. Example: 1:7 -> 0 [7 5 2] -> 1

Problem 135. inner product of two vectors Created by AMITAVA BISWAS in Community inner product of two vectors

Problem 18. Bullseye Matrix Created by Cody Team in Cody Challenge Given n (always odd), return output a that has concentric rings of the numbers 1 through (n 1)/2 around the center point. Examples: Input n = 3 Output a is [ 2 2 2 2 1 2 2 2 2 ] Input n = 5 Output a is [ 3 3 3 3 3 3 2 2 2 3 3 2 1 2 3 3 2 2 2 3 3 3 3 3 3 ]

Problem 40. Reverse Run-Length Encoder Created by Cody Team in Cody Challenge Given a "counting sequence" vector x, construct the original sequence y. A counting sequence is formed by "counting" the entries in a given sequence. This is sometimes called run-length encoding. For example, the sequence x = 2, 5, 1, 2, 4, 1, 1, 3 can be read as Two 5's, one 2, four 1's, one 3 which translates to y = 5, 5, 2, 1, 1, 1, 1, 3 So y is the reconstructed vector that corresponds to the counting seq...