check digit cases for Task 1 Perl script; Task 2 Partial Julia solution

2 files changed, 105 insertions, 1 deletions

diff --git a/challenge-162/cheok-yin-fung/julia/ch-2.jl b/challenge-162/cheok-yin-fung/julia/ch-2.jl
new file mode 100644
index 0000000000..12d3a012e6
--- /dev/null
+++ b/challenge-162/cheok-yin-fung/julia/ch-2.jl
@@ -0,0 +1,100 @@
+# The Weekly Challenge 162
+# Task 2 Wheatstone-Playfair cipher
+# Julia Solution, 
+#     Partial (only encrypt has been implemented yet)
+#         -- 1st May 2022 11AM HKT
+# Usage: codify( key , word-to-be-encrypted)
+
+using LinearAlgebra
+
+function only_special(c)
+    if c == "J"
+        return 'I'
+    else
+        return only(c)
+    end
+end
+
+
+
+function preprocess(word)
+    word = replace(uppercase(word), " " => "", "J" => "I")
+    word_a = split(word, "")
+    new_word_a = []
+    for i in 1:(length(word_a)-1)
+        push!(new_word_a, word_a[i])
+        if word_a[i] == word_a[i+1]
+            push!(new_word_a, "X")
+        end
+    end
+    new_word = join(new_word_a,"")*word_a[end]
+    return new_word
+end
+
+
+
+function pairup(word)
+    if length(word) % 2 == 1
+        word *= "X"
+    end
+    word_h = []
+    word_t = []
+    flip = true
+    for c in word
+        if flip
+            push!(word_h, c)
+        else
+            push!(word_t, c)
+        end
+        flip = !flip
+    end
+    return zip(word_h, word_t)
+end
+
+
+
+function playfair_board(key)
+    letters = unique(Base.vcat(
+        filter( c -> c != ' ' , 
+                only_special.(split(uppercase(key), ""))
+        ),
+        Char.(vcat(codepoint('A'):codepoint('I'), 
+                   codepoint('K'):codepoint('Z'))
+        )
+    ))
+
+    board_vv = [ letters[ 1:5], 
+                 letters[ 6:10],
+                 letters[11:15],
+                 letters[16:20],
+                 letters[21:25] ]
+    return Char.(transpose(codepoint.(reduce(hcat,board_vv))))
+                    # transpose(reduce(hcat,board_vv))  does not work!
+end
+
+
+
+function codify(key, word)
+    board = playfair_board(key)
+    zipped_words = pairup(preprocess(word))
+    encrypted_v = []
+    for p in collect(zipped_words)
+        (x1, y1) = Tuple(findfirst(c->c==first(p), board))
+        (x2, y2) = Tuple(findfirst(c->c== last(p), board))
+        if x1 == x2
+            push!(encrypted_v, board[x1, 1+y1%5] * board[x2, 1+y2%5])
+            continue
+        end
+        if y1 == y2
+            push!(encrypted_v, board[1+x1%5, y1] * board[1+x2%5, y2])
+            continue
+        end
+        push!(encrypted_v, board[x1,y2] * board[x2,y1])
+    end
+    
+    return join(encrypted_v, "")
+end
+
+
+
+# codify("playfair example", "hide the gold in the tree stump")
diff --git a/challenge-162/cheok-yin-fung/perl/ch-1.pl b/challenge-162/cheok-yin-fung/perl/ch-1.pl
index 95c0df5b10..b54c0590b8 100644
--- a/challenge-162/cheok-yin-fung/perl/ch-1.pl
+++ b/challenge-162/cheok-yin-fung/perl/ch-1.pl
@@ -34,9 +34,13 @@ sub valid {
 
 
 
-use Test::More tests => 5;
+use Test::More tests => 9;
 ok valid("978-0-306-40615-7"), "task example";
 ok valid("978-1-492-04503-8"), "Think Julia";
 ok valid("978-1-59327-666-9"), "How Software Works";
 ok valid("978-1-260-08450-4"), "Database System Concepts";
 ok !valid("123-4-567-89123-4"), "random strings of digits";
+ok 7==lookup("978-0-306-40615-?"), "(check digit) task example";
+ok 8==lookup("978-1-492-04503-?"), "(check digit) Think Julia";
+ok 9==lookup("978-1-59327-666-?"), "(check digit) How Software Works";
+ok 4==lookup("978-1-260-08450-?"), "(check digit) Database System Concepts";