Add Python solution to challenge 22

8 files changed, 168 insertions, 52 deletions

diff --git a/challenge-022/paulo-custodio/Makefile b/challenge-022/paulo-custodio/Makefile
new file mode 100644
index 0000000000..c3c762d746
--- /dev/null
+++ b/challenge-022/paulo-custodio/Makefile
@@ -0,0 +1,2 @@
+all:
+	perl ../../challenge-001/paulo-custodio/test.pl
diff --git a/challenge-022/paulo-custodio/perl/ch-1.pl b/challenge-022/paulo-custodio/perl/ch-1.pl
index 68e05cd91b..34225c0078 100644
--- a/challenge-022/paulo-custodio/perl/ch-1.pl
+++ b/challenge-022/paulo-custodio/perl/ch-1.pl
@@ -5,7 +5,7 @@
 # Task #1
 # Write a script to print first 10 Sexy Prime Pairs. Sexy primes are prime
 # numbers that differ from each other by 6. For example, the numbers 5 and 11
-# are both sexy primes, because 11 - 5 = 6. The term “sexy prime” is a pun
+# are both sexy primes, because 11 - 5 = 6. The term "sexy prime" is a pun
 # stemming from the Latin word for six: sex. For more information, please
 # checkout wiki page.
 
diff --git a/challenge-022/paulo-custodio/perl/ch-2.pl b/challenge-022/paulo-custodio/perl/ch-2.pl
index 878d0162b9..27fd92c867 100644
--- a/challenge-022/paulo-custodio/perl/ch-2.pl
+++ b/challenge-022/paulo-custodio/perl/ch-2.pl
@@ -3,7 +3,7 @@
 # Challenge 022
 #
 # Task #2
-# Write a script to implement Lempel–Ziv–Welch (LZW) compression algorithm.
+# Write a script to implement Lempel-Ziv-Welch (LZW) compression algorithm.
 # The script should have method to encode/decode algorithm. The wiki page
 # explains the compression algorithm very nicely.
 
diff --git a/challenge-022/paulo-custodio/python/ch-1.py b/challenge-022/paulo-custodio/python/ch-1.py
new file mode 100644
index 0000000000..346c160fb4
--- /dev/null
+++ b/challenge-022/paulo-custodio/python/ch-1.py
@@ -0,0 +1,39 @@
+#!/usr/bin/python3
+
+# Challenge 022
+#
+# Task #1
+# Write a script to print first 10 Sexy Prime Pairs. Sexy primes are prime
+# numbers that differ from each other by 6. For example, the numbers 5 and 11
+# are both sexy primes, because 11 - 5 = 6. The term "sexy prime" is a pun
+# stemming from the Latin word for six: sex. For more information, please
+# checkout wiki page.
+
+import sys
+from primePy import primes
+
+def next_prime(n):
+    if n <= 1:
+        return 2
+    else:
+        n += 1
+        while not primes.check(n):
+            n += 1
+        return n
+
+def sexy_primes_iter():
+    a = 1
+    while True:
+        a = next_prime(a)
+        b = a
+        while b < a+6:
+            b = next_prime(b)
+        if b == a+6:
+            yield (a, b)
+
+count = 0
+for a, b in sexy_primes_iter():
+    print(f"({a}, {b})")
+    count += 1
+    if count >= 10:
+        break
diff --git a/challenge-022/paulo-custodio/python/ch-2.py b/challenge-022/paulo-custodio/python/ch-2.py
new file mode 100644
index 0000000000..8900cf37cd
--- /dev/null
+++ b/challenge-022/paulo-custodio/python/ch-2.py
@@ -0,0 +1,100 @@
+#!/usr/bin/python3
+
+# Challenge 022
+#
+# Task #2
+# Write a script to implement Lempel-Ziv-Welch (LZW) compression algorithm.
+# The script should have method to encode/decode algorithm. The wiki page
+# explains the compression algorithm very nicely.
+
+import sys
+
+class Dict():
+    EOM = '#'
+    SYMBOLS = ['A','B','C','D','E','F','G','H','I','J','K','L','M',
+               'N','O','P','Q','R','S','T','U','V','W','X','Y','Z']
+
+    def __init__(self):
+        self.dict = {}
+        self.symbols = []
+        for sym in [Dict.EOM, *Dict.SYMBOLS]:
+            self.add(sym)
+
+    def __str__(self):
+        return "dict="+str(self.dict)+",symbols="+str(self.symbols)
+
+    def last(self):
+        return len(self.symbols)-1
+
+    def width(self):
+        return len("{:b}".format(self.last()))
+
+    def next_width(self):
+        return len("{:b}".format(self.last()+1))
+
+    def add(self, seq):
+        seq = seq.upper()
+
+        id = self.last()+1
+        self.dict[seq] = id
+        self.symbols.append(seq)
+
+    def longest_match(self, text):
+        text = text.upper()
+
+        # find longest match
+        match_len = 0
+        while match_len < len(text) and \
+              text[:match_len+1] in self.dict:
+            match_len += 1
+        w = text[:match_len]
+        text = text[match_len:]
+        code = self.dict[w]
+        old_width = self.width()
+
+        # store new prefix in the dictionary
+        if text != "":
+            next_prefix = w+text[0]
+            self.add(next_prefix)
+
+        # return code and new text
+        return ("{:0"+str(old_width)+"b}").format(code), text
+
+def encode(text):
+    text = text.upper()+Dict.EOM
+    encoded = ""
+    dict = Dict()
+
+    while text != "":
+        code, text = dict.longest_match(text)
+        encoded += code
+
+    return encoded
+
+def decode(encoded):
+    text = ""
+    dict = Dict()
+
+    while encoded != "":
+        width = dict.width()
+        code = int(encoded[:width], 2)
+        encoded = encoded[width:]
+        seq = dict.symbols[code]
+        text += seq
+
+        if encoded != "":
+            next_width = dict.next_width()
+            next_code = int(encoded[:next_width], 2)
+            next_seq = dict.symbols[next_code]
+            dict.add(seq + next_seq[0])
+
+    # remove end terminator
+    text = text[:-1]
+    return text
+
+if sys.argv[1] == "encode":
+    print(encode(sys.argv[2]))
+elif sys.argv[1] == "decode":
+    print(decode(sys.argv[2]))
+else:
+    print("Usage: ch-2.py encode|decode text")
diff --git a/challenge-022/paulo-custodio/t/test-1.yaml b/challenge-022/paulo-custodio/t/test-1.yaml
new file mode 100644
index 0000000000..f5b7fc6388
--- /dev/null
+++ b/challenge-022/paulo-custodio/t/test-1.yaml
@@ -0,0 +1,15 @@
+- setup:
+  cleanup:
+  args:
+  input:
+  output:   |
+            (5, 11)
+            (7, 13)
+            (11, 17)
+            (13, 19)
+            (17, 23)
+            (23, 29)
+            (31, 37)
+            (37, 43)
+            (41, 47)
+            (47, 53)
diff --git a/challenge-022/paulo-custodio/t/test-2.yaml b/challenge-022/paulo-custodio/t/test-2.yaml
new file mode 100644
index 0000000000..06a3467c73
--- /dev/null
+++ b/challenge-022/paulo-custodio/t/test-2.yaml
@@ -0,0 +1,10 @@
+- setup:
+  cleanup:
+  args:     encode TOBEORNOTTOBEORTOBEORNOT
+  input:
+  output:   101000111100010001010111110010001110001111010100011011011101011111100100011110100000100010000000
+- setup:
+  cleanup:
+  args:     decode 101000111100010001010111110010001110001111010100011011011101011111100100011110100000100010000000
+  input:
+  output:   TOBEORNOTTOBEORTOBEORNOT
diff --git a/challenge-022/paulo-custodio/test.pl b/challenge-022/paulo-custodio/test.pl
deleted file mode 100644
index 4fb163a066..0000000000
--- a/challenge-022/paulo-custodio/test.pl
+++ /dev/null
@@ -1,50 +0,0 @@
-#!/usr/bin/perl
-
-use Modern::Perl;
-use Test::More;
-
-is capture("perl perl/ch-1.pl"), <<END;
-(5, 11)
-(7, 13)
-(11, 17)
-(13, 19)
-(17, 23)
-(23, 29)
-(31, 37)
-(37, 43)
-(41, 47)
-(47, 53)
-END
-
-my($text, $encoded) = ("TOBEORNOTTOBEORTOBEORNOT", join("", qw(
-                      10100
-                      01111
-                      00010
-                      00101
-                      01111
-                      10010
-                      001110
-                      001111
-                      010100
-                      011011
-                      011101
-                      011111
-                      100100
-                      011110
-                      100000
-                      100010
-                      000000
-                      )));
-
-is capture("perl perl/ch-2.pl encode $text"), "$encoded\n", "$text -> $encoded";
-is capture("perl perl/ch-2.pl decode $encoded"), "$text\n", "$encoded -> $text";
-
-done_testing;
-
-
-sub capture {
-    my($cmd) = @_;
-    my $out = `$cmd`;
-    $out =~ s/[ \t\v\f\r]*\n/\n/g;
-    return $out;
-}