Merge pull request #5196 from pauloscustodio/devel

Add Python solution to challenge 87

32 files changed, 785 insertions, 243 deletions

diff --git a/challenge-084/paulo-custodio/Makefile b/challenge-084/paulo-custodio/Makefile
new file mode 100644
index 0000000000..c3c762d746
--- /dev/null
+++ b/challenge-084/paulo-custodio/Makefile
@@ -0,0 +1,2 @@
+all:
+	perl ../../challenge-001/paulo-custodio/test.pl
diff --git a/challenge-084/paulo-custodio/perl/ch-1.pl b/challenge-084/paulo-custodio/perl/ch-1.pl
index c81e86db18..6082b77511 100644
--- a/challenge-084/paulo-custodio/perl/ch-1.pl
+++ b/challenge-084/paulo-custodio/perl/ch-1.pl
@@ -1,13 +1,13 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Challenge 084
 #
-# TASK #1 › Reverse Integer
+# TASK #1 > Reverse Integer
 # Submitted by: Mohammad S Anwar
 # You are given an integer $N.
 #
 # Write a script to reverse the given integer and print the result. Print 0 if
-# the result doesn’t fit in 32-bit signed integer.
+# the result doesn't fit in 32-bit signed integer.
 #
 # The number 2,147,483,647 is the maximum positive value for a 32-bit signed binary
 # integer in computing.
diff --git a/challenge-084/paulo-custodio/perl/ch-2.pl b/challenge-084/paulo-custodio/perl/ch-2.pl
index 000dfe2589..242cc569a1 100644
--- a/challenge-084/paulo-custodio/perl/ch-2.pl
+++ b/challenge-084/paulo-custodio/perl/ch-2.pl
@@ -2,7 +2,7 @@
 
 # Challenge 084
 #
-# TASK #2 › Find Square
+# TASK #2 > Find Square
 # Submitted by: Mohammad S Anwar
 # You are given matrix of size m x n with only 1 and 0.
 #
@@ -16,7 +16,8 @@
 #
 # Output: 1
 # Explanation:
-# There is one square (3x3) in the given matrix with four corners as 1 starts at r=1;c=2.
+# There is one square (3x3) in the given matrix with four corners as 1 starts
+# at r=1;c=2.
 # [ 1 0 1 ]
 # [ 0 1 0 ]
 # [ 1 0 1 ]
@@ -28,10 +29,12 @@
 #
 # Output: 4
 # Explanation:
-# There is one square (4x4) in the given matrix with four corners as 1 starts at r=1;c=1.
-# There is one square (3x3) in the given matrix with four corners as 1 starts at r=1;c=2.
-# There are two squares (2x2) in the given matrix with four corners as 1. First starts
-# at r=1;c=1 and second starts at r=3;c=3.
+# There is one square (4x4) in the given matrix with four corners as 1 starts
+# at r=1;c=1.
+# There is one square (3x3) in the given matrix with four corners as 1 starts
+# at r=1;c=2.
+# There are two squares (2x2) in the given matrix with four corners as 1.
+# First starts at r=1;c=1 and second starts at r=3;c=3.
 # Example 3:
 # Input: [ 0 1 0 1 ]
 #        [ 1 0 1 0 ]
diff --git a/challenge-084/paulo-custodio/python/ch-1.py b/challenge-084/paulo-custodio/python/ch-1.py
new file mode 100644
index 0000000000..6fc8d909f9
--- /dev/null
+++ b/challenge-084/paulo-custodio/python/ch-1.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+
+# Challenge 084
+#
+# TASK #1 > Reverse Integer
+# Submitted by: Mohammad S Anwar
+# You are given an integer $N.
+#
+# Write a script to reverse the given integer and print the result. Print 0 if
+# the result doesn't fit in 32-bit signed integer.
+#
+# The number 2,147,483,647 is the maximum positive value for a 32-bit signed binary
+# integer in computing.
+#
+# Example 1:
+# Input: 1234
+# Output: 4321
+# Example 2:
+# Input: -1234
+# Output: -4321
+# Example 3:
+# Input: 1231230512
+# Output: 0
+
+import sys
+
+def reverse_int(n):
+    if n < -0x80000000 or n > 0x7fffffff:
+        return 0
+    rev = 0
+    if n < 0:
+        sign = -1
+        n = -n
+    else:
+        sign = 1
+    while n > 0:
+        rev = 10 * rev + n%10
+        n //= 10
+    rev *= sign
+    return rev
+
+print(reverse_int(int(sys.argv[1])))
diff --git a/challenge-084/paulo-custodio/python/ch-2.py b/challenge-084/paulo-custodio/python/ch-2.py
new file mode 100644
index 0000000000..760041916e
--- /dev/null
+++ b/challenge-084/paulo-custodio/python/ch-2.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+
+# Challenge 084
+#
+# TASK #2 > Find Square
+# Submitted by: Mohammad S Anwar
+# You are given matrix of size m x n with only 1 and 0.
+#
+# Write a script to find the count of squares having all four corners set as 1.
+#
+# Example 1:
+# Input: [ 0 1 0 1 ]
+#        [ 0 0 1 0 ]
+#        [ 1 1 0 1 ]
+#        [ 1 0 0 1 ]
+#
+# Output: 1
+# Explanation:
+# There is one square (3x3) in the given matrix with four corners as 1 starts
+# at r=1;c=2.
+# [ 1 0 1 ]
+# [ 0 1 0 ]
+# [ 1 0 1 ]
+# Example 2:
+# Input: [ 1 1 0 1 ]
+#        [ 1 1 0 0 ]
+#        [ 0 1 1 1 ]
+#        [ 1 0 1 1 ]
+#
+# Output: 4
+# Explanation:
+# There is one square (4x4) in the given matrix with four corners as 1 starts
+# at r=1;c=1.
+# There is one square (3x3) in the given matrix with four corners as 1 starts
+# at r=1;c=2.
+# There are two squares (2x2) in the given matrix with four corners as 1.
+# First starts at r=1;c=1 and second starts at r=3;c=3.
+# Example 3:
+# Input: [ 0 1 0 1 ]
+#        [ 1 0 1 0 ]
+#        [ 0 1 0 0 ]
+#        [ 1 0 0 1 ]
+#
+# Output: 0
+
+import fileinput
+import re
+
+def read_input():
+    lines = []
+    for line in fileinput.input():
+        lines.append(line)
+    return lines
+
+def read_matrix(lines):
+    m = []
+    for line in lines:
+        line = re.sub(r"\D+", " ", line)
+        cols = [int(x) for x in line.split()]
+        m.append(cols)
+    return m
+
+def count_squares(m):
+    nrows = len(m)
+    ncols = len(m[0])
+    if nrows < 2 or ncols < 2:
+        return 0
+
+    count = 0
+    for r in range(nrows):
+        for c in range(ncols):
+            if m[r][c]:
+                d = 1
+                while r+d < nrows and c+d < ncols:
+                    if m[r+d][c] and m[r][c+d] and m[r+d][c+d]:
+                        count += 1
+                    d += 1
+
+    return count
+
+print(count_squares(read_matrix(read_input())))
diff --git a/challenge-084/paulo-custodio/t/test-1.yaml b/challenge-084/paulo-custodio/t/test-1.yaml
new file mode 100644
index 0000000000..3b31c13a7f
--- /dev/null
+++ b/challenge-084/paulo-custodio/t/test-1.yaml
@@ -0,0 +1,45 @@
+- setup:
+  cleanup:
+  args:     1
+  input:
+  output:   1
+- setup:
+  cleanup:
+  args:     0
+  input:
+  output:   0
+- setup:
+  cleanup:
+  args:     -1
+  input:
+  output:   -1
+- setup:
+  cleanup:
+  args:     1234
+  input:
+  output:   4321
+- setup:
+  cleanup:
+  args:     -1234
+  input:
+  output:   -4321
+- setup:
+  cleanup:
+  args:     -2147483649
+  input:
+  output:   0
+- setup:
+  cleanup:
+  args:     -2147483648
+  input:
+  output:   -8463847412
+- setup:
+  cleanup:
+  args:     2147483647
+  input:
+  output:   7463847412
+- setup:
+  cleanup:
+  args:     2147483648
+  input:
+  output:   0
diff --git a/challenge-084/paulo-custodio/t/test-2.yaml b/challenge-084/paulo-custodio/t/test-2.yaml
new file mode 100644
index 0000000000..f6fd98235b
--- /dev/null
+++ b/challenge-084/paulo-custodio/t/test-2.yaml
@@ -0,0 +1,27 @@
+- setup:
+  cleanup:
+  args:
+  input:    |
+            [ 0 1 0 1 ]
+            [ 0 0 1 0 ]
+            [ 1 1 0 1 ]
+            [ 1 0 0 1 ]
+  output:   1
+- setup:
+  cleanup:
+  args:
+  input:    |
+            [ 1 1 0 1 ]
+            [ 1 1 0 0 ]
+            [ 0 1 1 1 ]
+            [ 1 0 1 1 ]
+  output:   4
+- setup:
+  cleanup:
+  args:
+  input:    |
+            [ 0 1 0 1 ]
+            [ 1 0 1 0 ]
+            [ 0 1 0 0 ]
+            [ 1 0 0 1 ]
+  output:   0
diff --git a/challenge-084/paulo-custodio/test.pl b/challenge-084/paulo-custodio/test.pl
deleted file mode 100644
index 91fde37cc1..0000000000
--- a/challenge-084/paulo-custodio/test.pl
+++ /dev/null
@@ -1,57 +0,0 @@
-#!/usr/bin/perl
-
-use Modern::Perl;
-use Test::More;
-
-my $in = "in.txt";
-
-is capture("perl/ch-1.pl 1"),           "1\n";
-is capture("perl/ch-1.pl 0"),           "0\n";
-is capture("perl/ch-1.pl -1"),          "-1\n";
-is capture("perl/ch-1.pl 1234"),        "4321\n";
-is capture("perl/ch-1.pl -1234"),       "-4321\n";
-is capture("perl/ch-1.pl -2147483649"), "0\n";
-is capture("perl/ch-1.pl -2147483648"), "-8463847412\n";
-is capture("perl/ch-1.pl  2147483647"), "7463847412\n";
-is capture("perl/ch-1.pl  2147483648"), "0\n";
-
-spew($in, <<END);
-[ 0 1 0 1 ]
-[ 0 0 1 0 ]
-[ 1 1 0 1 ]
-[ 1 0 0 1 ]
-END
-is capture("perl perl/ch-2.pl <$in"), "1\n";
-
-spew($in, <<END);
-[ 1 1 0 1 ]
-[ 1 1 0 0 ]
-[ 0 1 1 1 ]
-[ 1 0 1 1 ]
-END
-is capture("perl perl/ch-2.pl <$in"), "4\n";
-
-spew($in, <<END);
-[ 0 1 0 1 ]
-[ 1 0 1 0 ]
-[ 0 1 0 0 ]
-[ 1 0 0 1 ]
-END
-is capture("perl perl/ch-2.pl <$in"), "0\n";
-
-
-unlink($in);
-done_testing;
-
-sub capture {
-    my($cmd) = @_;
-    my $out = `$cmd`;
-    $out =~ s/[ \t\v\f\r]*\n/\n/g;
-    return $out;
-}
-
-sub spew {
-    my($file, $text) = @_;
-    open(my $fh, ">", $file) or die "write $file: $!\n";
-    print $fh $text;
-}
diff --git a/challenge-085/paulo-custodio/Makefile b/challenge-085/paulo-custodio/Makefile
new file mode 100644
index 0000000000..c3c762d746
--- /dev/null
+++ b/challenge-085/paulo-custodio/Makefile
@@ -0,0 +1,2 @@
+all:
+	perl ../../challenge-001/paulo-custodio/test.pl
diff --git a/challenge-085/paulo-custodio/perl/ch-1.pl b/challenge-085/paulo-custodio/perl/ch-1.pl
index a471b54e85..6037ae6976 100644
--- a/challenge-085/paulo-custodio/perl/ch-1.pl
+++ b/challenge-085/paulo-custodio/perl/ch-1.pl
@@ -1,12 +1,13 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Challenge 085
 #
-# TASK #1 › Triplet Sum
+# TASK #1 > Triplet Sum
 # Submitted by: Mohammad S Anwar
 # You are given an array of real numbers greater than zero.
 #
-# Write a script to find if there exists a triplet (a,b,c) such that 1 < a+b+c < 2. Print 1 if you succeed otherwise 0.
+# Write a script to find if there exists a triplet (a,b,c) such that
+# 1 < a+b+c < 2. Print 1 if you succeed otherwise 0.
 #
 # Example 1:
 # Input: @R = (1.2, 0.4, 0.1, 2.5)
diff --git a/challenge-085/paulo-custodio/perl/ch-2.pl b/challenge-085/paulo-custodio/perl/ch-2.pl
index c0a16a4221..4b0f2447f4 100644
--- a/challenge-085/paulo-custodio/perl/ch-2.pl
+++ b/challenge-085/paulo-custodio/perl/ch-2.pl
@@ -1,12 +1,13 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Challenge 085
 #
-# TASK #2 › Power of Two Integers
+# TASK #2 > Power of Two Integers
 # Submitted by: Mohammad S Anwar
 # You are given a positive integer $N.
 #
-# Write a script to find if it can be expressed as a ** b where a > 0 and b > 1. Print 1 if you succeed otherwise 0.
+# Write a script to find if it can be expressed as a ** b where
+# a > 0 and b > 1. Print 1 if you succeed otherwise 0.
 #
 # Example 1:
 # Input: 8
diff --git a/challenge-085/paulo-custodio/python/ch-1.py b/challenge-085/paulo-custodio/python/ch-1.py
new file mode 100644
index 0000000000..54f9e1cd1b
--- /dev/null
+++ b/challenge-085/paulo-custodio/python/ch-1.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+
+# Challenge 085
+#
+# TASK #1 > Triplet Sum
+# Submitted by: Mohammad S Anwar
+# You are given an array of real numbers greater than zero.
+#
+# Write a script to find if there exists a triplet (a,b,c) such that
+# 1 < a+b+c < 2. Print 1 if you succeed otherwise 0.
+#
+# Example 1:
+# Input: @R = (1.2, 0.4, 0.1, 2.5)
+# Output: 1 as 1 < 1.2 + 0.4 + 0.1 < 2
+# Example 2:
+# Input: @R = (0.2, 1.5, 0.9, 1.1)
+# Output: 0
+# Example 3:
+# Input: @R = (0.5, 1.1, 0.3, 0.7)
+# Output: 1 as 1 < 0.5 + 1.1 + 0.3 < 2
+
+import sys
+from itertools import combinations
+
+def check(nums):
+    for combin in combinations(nums, 3):
+        if 1.0 < sum(combin) < 2.0:
+            return True
+    return False
+
+print(1 if check([float(x) for x in sys.argv[1:]]) else 0)
diff --git a/challenge-085/paulo-custodio/python/ch-2.py b/challenge-085/paulo-custodio/python/ch-2.py
new file mode 100644
index 0000000000..ef869c12f8
--- /dev/null
+++ b/challenge-085/paulo-custodio/python/ch-2.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+
+# Challenge 085
+#
+# TASK #2 > Power of Two Integers
+# Submitted by: Mohammad S Anwar
+# You are given a positive integer $N.
+#
+# Write a script to find if it can be expressed as a ** b where
+# a > 0 and b > 1. Print 1 if you succeed otherwise 0.
+#
+# Example 1:
+# Input: 8
+# Output: 1 as 8 = 2 ** 3
+# Example 2:
+# Input: 15
+# Output: 0
+# Example 3:
+# Input: 125
+# Output: 1 as 125 = 5 ** 3
+
+import sys
+
+def get_prime_factors(n):
+    i = 2
+    prime_factors = []
+    while i*i <= n:
+        if n%i == 0:
+            prime_factors.append(i)
+            n //= i
+        else:
+            i += 1
+
+    if n>1:
+        prime_factors.append(n)
+
+    return prime_factors
+
+def is_perfect_power(n):
+    factors = list(set(get_prime_factors(n)))
+    return len(factors)==1
+
+print(1 if is_perfect_power(int(sys.argv[1])) else 0)
diff --git a/challenge-085/paulo-custodio/t/test-1.yaml b/challenge-085/paulo-custodio/t/test-1.yaml
new file mode 100644
index 0000000000..f382a0db0c
--- /dev/null
+++ b/challenge-085/paulo-custodio/t/test-1.yaml
@@ -0,0 +1,15 @@
+- setup:
+  cleanup:
+  args:     1.2 0.4 0.1 2.5
+  input:
+  output:   1
+- setup:
+  cleanup:
+  args:     0.2 1.5 0.9 1.1
+  input:
+  output:   0
+- setup:
+  cleanup:
+  args:     0.5 1.1 0.3 0.7
+  input:
+  output:   1
diff --git a/challenge-085/paulo-custodio/t/test-2.yaml b/challenge-085/paulo-custodio/t/test-2.yaml
new file mode 100644
index 0000000000..1e3f9f6071
--- /dev/null
+++ b/challenge-085/paulo-custodio/t/test-2.yaml
@@ -0,0 +1,15 @@
+- setup:
+  cleanup:
+  args:     8
+  input:
+  output:   1
+- setup:
+  cleanup:
+  args:     15
+  input:
+  output:   0
+- setup:
+  cleanup:
+  args:     125
+  input:
+  output:   1
diff --git a/challenge-085/paulo-custodio/test.pl b/challenge-085/paulo-custodio/test.pl
deleted file mode 100644
index b32170a073..0000000000
--- a/challenge-085/paulo-custodio/test.pl
+++ /dev/null
@@ -1,21 +0,0 @@
-#!/usr/bin/perl
-
-use Modern::Perl;
-use Test::More;
-
-is capture("perl/ch-1.pl 1.2 0.4 0.1 2.5"), "1\n";
-is capture("perl/ch-1.pl 0.2 1.5 0.9 1.1"), "0\n";
-is capture("perl/ch-1.pl 0.5 1.1 0.3 0.7"), "1\n";
-
-is capture("perl/ch-2.pl   8"), "1\n";
-is capture("perl/ch-2.pl  15"), "0\n";
-is capture("perl/ch-2.pl 125"), "1\n";
-
-done_testing;
-
-sub capture {
-    my($cmd) = @_;
-    my $out = `$cmd`;
-    $out =~ s/[ \t\v\f\r]*\n/\n/g;
-    return $out;
-}
diff --git a/challenge-086/paulo-custodio/Makefile b/challenge-086/paulo-custodio/Makefile
new file mode 100644
index 0000000000..c3c762d746
--- /dev/null
+++ b/challenge-086/paulo-custodio/Makefile
@@ -0,0 +1,2 @@
+all:
+	perl ../../challenge-001/paulo-custodio/test.pl
diff --git a/challenge-086/paulo-custodio/perl/ch-1.pl b/challenge-086/paulo-custodio/perl/ch-1.pl
index 9164d0b630..281cfd766c 100644
--- a/challenge-086/paulo-custodio/perl/ch-1.pl
+++ b/challenge-086/paulo-custodio/perl/ch-1.pl
@@ -1,8 +1,8 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Challenge 086
 
-# TASK #1 › Pair Difference
+# TASK #1 > Pair Difference
 # Submitted by: Mohammad S Anwar
 # You are given an array of integers @N and an integer $A.
 #
diff --git a/challenge-086/paulo-custodio/perl/ch-2.pl b/challenge-086/paulo-custodio/perl/ch-2.pl
index d13376b053..27f6626469 100644
--- a/challenge-086/paulo-custodio/perl/ch-2.pl
+++ b/challenge-086/paulo-custodio/perl/ch-2.pl
@@ -1,8 +1,8 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 # Challenge 086
 
-# TASK #2 › Sudoku Puzzle
+# TASK #2 > Sudoku Puzzle
 # Submitted by: Mohammad S Anwar
 # You are given Sudoku puzzle (9x9).
 #
diff --git a/challenge-086/paulo-custodio/python/ch-1.py b/challenge-086/paulo-custodio/python/ch-1.py
new file mode 100644
index 0000000000..7f3af4aa62
--- /dev/null
+++ b/challenge-086/paulo-custodio/python/ch-1.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+
+# Challenge 086
+
+# TASK #1 > Pair Difference
+# Submitted by: Mohammad S Anwar
+# You are given an array of integers @N and an integer $A.
+#
+# Write a script to find find if there exists a pair of elements in the array whose difference is $A.
+#
+# Print 1 if exists otherwise 0.
+#
+# Example 1:
+# Input: @N = (10, 8, 12, 15, 5) and $A = 7
+# Output: 1 as 15 - 8 = 7
+# Example 2:
+# Input: @N = (1, 5, 2, 9, 7) and $A = 6
+# Output: 1 as 7 - 1 = 6
+# Example 3:
+# Input: @N = (10, 30, 20, 50, 40) and $A = 15
+# Output: 0
+
+import sys
+
+def found(dif, nums):
+    for i in range(len(nums)-1):
+        for j in range(i+1, len(nums)):
+            if abs(nums[i]-nums[j])==dif:
+                return True
+    return False
+
+nums = [int(x) for x in sys.argv[1:]]
+dif = nums.pop(-1)
+if found(dif, nums):
+    print(1)
+else:
+    print(0)
diff --git a/challenge-086/paulo-custodio/python/ch-2.py b/challenge-086/paulo-custodio/python/ch-2.py
new file mode 100644
index 0000000000..c0724735ca
--- /dev/null
+++ b/challenge-086/paulo-custodio/python/ch-2.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+
+# Challenge 086
+
+# TASK #2 > Sudoku Puzzle
+# Submitted by: Mohammad S Anwar
+# You are given Sudoku puzzle (9x9).
+#
+# Write a script to complete the puzzle and must respect the following rules:
+#
+# a) Each row must have the numbers 1-9 occurring just once.
+# b) Each column must have the numbers 1-9 occurring just once.
+# c) The numbers 1-9 must occur just once in each of the 9 sub-boxes (3x3) of the grid.
+# Example:
+# [ _ _ _ 2 6 _ 7 _ 1 ]
+# [ 6 8 _ _ 7 _ _ 9 _ ]
+# [ 1 9 _ _ _ 4 5 _ _ ]
+# [ 8 2 _ 1 _ _ _ 4 _ ]
+# [ _ _ 4 6 _ 2 9 _ _ ]
+# [ _ 5 _ _ _ 3 _ 2 8 ]
+# [ _ _ 9 3 _ _ _ 7 4 ]
+# [ _ 4 _ _ 5 _ _ 3 6 ]
+# [ 7 _ 3 _ 1 8 _ _ _ ]
+# Output:
+# [ 4 3 5 2 6 9 7 8 1 ]
+# [ 6 8 2 5 7 1 4 9 3 ]
+# [ 1 9 7 8 3 4 5 6 2 ]
+# [ 8 2 6 1 9 5 3 4 7 ]
+# [ 3 7 4 6 8 2 9 1 5 ]
+# [ 9 5 1 7 4 3 6 2 8 ]
+# [ 5 1 9 3 2 6 8 7 4 ]
+# [ 2 4 8 9 5 7 1 3 6 ]
+# [ 7 6 3 4 1 8 2 5 9 ]
+# As the above puzzle respect the 3 rules including 9-sub-boxes as shown below:
+#
+# [ 4 3 5 ] [ 2 6 9 ] [ 7 8 1 ]
+# [ 6 8 2 ] [ 5 7 1 ] [ 4 9 3 ]
+# [ 1 9 7 ] [ 8 3 4 ] [ 5 6 2 ]
+#
+# [ 8 2 6 ] [ 1 9 5 ] [ 3 4 7 ]
+# [ 3 7 4 ] [ 6 8 2 ] [ 9 1 5 ]
+# [ 9 5 1 ] [ 7 4 3 ] [ 6 2 8 ]
+#
+# [ 5 1 9 ] [ 3 2 6 ] [ 8 7 4 ]
+# [ 2 4 8 ] [ 9 5 7 ] [ 1 3 6 ]
+# [ 7 6 3 ] [ 4 1 8 ] [ 2 5 9 ]
+
+import fileinput
+import re
+import copy
+
+def read_input():
+    lines = []
+    for line in fileinput.input():
+        lines.append(line)
+    return lines
+
+def read_matrix(lines):
+    m = []
+    for line in lines:
+        line = re.sub(r"_", "0", line)
+        line = re.sub(r"\D+", " ", line)
+        cols = [int(x) for x in line.split()]
+        m.append(cols)
+    return m
+
+# check no position violates the three rules
+def check_constraints(m):
+    # a) Each row must have the numbers 1-9 occurring just once.
+    for c in range(len(m[0])):
+        found = set()
+        for r in range(len(m)):
+            v = m[r][c]
+            if v > 0 and v in found:
+                return False
+            else:
+                found.add(v)
+
+    # b) Each column must have the numbers 1-9 occurring just once.
+    for r in range(len(m)):
+        found = set()
+        for c in range(len(m[0])):
+            v = m[r][c]
+            if v > 0 and v in found:
+                return False
+            else:
+                found.add(v)
+
+    # c) The numbers 1-9 must occur just once in each of the 9 sub-boxes (3x3) of the grid.
+    for r0 in range(0, len(m), 3):
+        for c0 in range(0, len(m[0]), 3):
+            found = set()
+            for r in range(r0, r0+3):
+                for c in range(c0, c0+3):
+                    v = m[r][c]
+                    if v > 0 and v in found:
+                        return False
+                    else:
+                        found.add(v)
+
+    return True
+
+def solve(m):
+    if not check_constraints(m):
+        return
+
+    for r in range(len(m)):
+        for c in range(len(m[0])):
+            if m[r][c]==0:
+                for v in range(1, 10):
+                    mcpy = copy.deepcopy(m)
+                    mcpy[r][c] = v
+                    solve(mcpy)
+                return              # trim the tree, we have tried 1..9
+
+    # all solved, output result
+    for row in m:
+        print("[ "+ " ".join([str(x) for x in row]) +" ]")
+    print("")
+
+
+solve(read_matrix(read_input()))
diff --git a/challenge-086/paulo-custodio/t/test-1.yaml b/challenge-086/paulo-custodio/t/test-1.yaml
new file mode 100644
index 0000000000..7632a2a806
--- /dev/null
+++ b/challenge-086/paulo-custodio/t/test-1.yaml
@@ -0,0 +1,15 @@
+- setup:
+  cleanup:
+  args:     10 8 12 15 5      7
+  input:
+  output:   1
+- setup:
+  cleanup:
+  args:     1 5 2 9 7         6
+  input:
+  output:   1
+- setup:
+  cleanup:
+  args:     10 30 20 50 40    15
+  input:
+  output:   0
diff --git a/challenge-086/paulo-custodio/t/test-2.yaml b/challenge-086/paulo-custodio/t/test-2.yaml
new file mode 100644
index 0000000000..a082b670a7
--- /dev/null
+++ b/challenge-086/paulo-custodio/t/test-2.yaml
@@ -0,0 +1,24 @@
+- setup:
+  cleanup:
+  args:
+  input:    |
+            [ _ _ _ 2 6 _ 7 _ 1 ]
+            [ 6 8 _ _ 7 _ _ 9 _ ]
+            [ 1 9 _ _ _ 4 5 _ _ ]
+            [ 8 2 _ 1 _ _ _ 4 _ ]
+            [ _ _ 4 6 _ 2 9 _ _ ]
+            [ _ 5 _ _ _ 3 _ 2 8 ]
+            [ _ _ 9 3 _ _ _ 7 4 ]
+            [ _ 4 _ _ 5 _ _ 3 6 ]
+            [ 7 _ 3 _ 1 8 _ _ _ ]
+  output:   |
+            |[ 4 3 5 2 6 9 7 8 1 ]
+            |[ 6 8 2 5 7 1 4 9 3 ]
+            |[ 1 9 7 8 3 4 5 6 2 ]
+            |[ 8 2 6 1 9 5 3 4 7 ]
+            |[ 3 7 4 6 8 2 9 1 5 ]
+            |[ 9 5 1 7 4 3 6 2 8 ]
+            |[ 5 1 9 3 2 6 8 7 4 ]
+            |[ 2 4 8 9 5 7 1 3 6 ]
+            |[ 7 6 3 4 1 8 2 5 9 ]
+            |
diff --git a/challenge-086/paulo-custodio/test.pl b/challenge-086/paulo-custodio/test.pl
deleted file mode 100644
index 529f841c6c..0000000000
--- a/challenge-086/paulo-custodio/test.pl
+++ /dev/null
@@ -1,50 +0,0 @@
-#!/usr/bin/perl
-
-use Modern::Perl;
-use Test::More;
-
-my $in = "in.txt";
-
-is capture("perl perl/ch-1.pl 10 8 12 15 5       7"), "1\n";
-is capture("perl perl/ch-1.pl 1 5 2 9 7          6"), "1\n";
-is capture("perl perl/ch-1.pl 10 30 20 50 40    15"), "0\n";
-
-
-spew($in, <<END);
-[ _ _ _ 2 6 _ 7 _ 1 ]
-[ 6 8 _ _ 7 _ _ 9 _ ]
-[ 1 9 _ _ _ 4 5 _ _ ]
-[ 8 2 _ 1 _ _ _ 4 _ ]
-[ _ _ 4 6 _ 2 9 _ _ ]
-[ _ 5 _ _ _ 3 _ 2 8 ]
-[ _ _ 9 3 _ _ _ 7 4 ]
-[ _ 4 _ _ 5 _ _ 3 6 ]
-[ 7 _ 3 _ 1 8 _ _ _ ]
-END
-is capture("perl perl/ch-2.pl <$in"), <<END;
-[ 4 3 5 2 6 9 7 8 1 ]
-[