Solve problem 4 task 1

2020-05-10 14:23:06 +02:00 · 2020-05-10 14:23:06 +02:00 · 1b69aed5e9
commit 1b69aed5e9
parent d5d2bbb2cc
2 changed files with 11 additions and 3 deletions
--- a/Contest2020/Contest2020.dyalog
+++ b/Contest2020/Contest2020.dyalog
@ -39,10 +39,18 @@
                  urls←('https://www.dyalog.com/'∘,)¨paths
                ∇

-                ∇ r←revp dna
+                ⍝ Test if a DNA string is a reverse palindrome.
+                isrevp←{⍵≡⌽'TAGC'['ATCG'⍳⍵]}
+                ⍝ Generate all subarrays (position, length) pairs, for
+                ⍝ 4 ≤ length ≤ 12.
+                subarrays←{⊃,/(⍳⍵),¨¨3↓¨⍳¨12⌊1+⍵-⍳⍵}
+                ∇ r←revp dna;positions
                  ⍝ 2020 APL Problem Solving Competition Phase II
                  ⍝ Stub function for Problem 4, Task 1 - revp
                  ⍝ Put your code and comments below here
+                  positions←subarrays⍴dna
+                  ⍝ Filter subarrays which are reverse palindromes.
+                  r←↑({isrevp dna[¯1+⍵[1]+⍳⍵[2]]}¨positions)/positions
                ∇

                ∇ r←sset n
--- a/Contest2020/Data/rosalind_revp_2_output.txt
+++ b/Contest2020/Data/rosalind_revp_2_output.txt
@ -1,4 +1,4 @@
-1  4
+  1  4
  2  4
  3  4
 16  4