add recent solutions

4kyuSnail.rb

@@ -0,0 +1,59 @@
+def snail(array)
+  array_size = array.size
+  return [] if array.any?(&:empty?)
+  return [] if array_size != array[0].size
+
+  top, left, right, bottom = 0, 0, array_size-1, array_size-1
+  i, j = 0, 0
+  dir = :right
+  list = []
+
+  loop do
+    list << array[i][j]
+    # move ahead
+    if dir == :right
+      if j < right
+        j += 1
+      else
+        dir = :down
+        top += 1
+        i += 1
+        break if i > bottom
+      end
+    elsif dir == :down
+      if i < bottom
+        i += 1
+      else
+        dir = :left
+        right -= 1
+        j -= 1
+        break if j <= left
+      end
+    elsif dir == :left
+      if j > left
+        j -= 1
+      else
+        dir = :up
+        bottom -= 1
+        i -= 1
+        break if i < top
+      end
+    elsif dir == :up
+      if i > top
+        i -= 1
+      else
+        dir = :right
+        left += 1
+        j += 1
+        break if j >= right
+      end
+    end
+  end
+
+  list << array[i][j] if array[i] && array[i][j]
+  list
+end
+
+p snail([[1]])
+p snail([[1,2,3],[4,5,6],[7,8,9]])
+p snail([[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]])

4kyuStripComments.rb

@@ -0,0 +1,13 @@
+def solution(input, markers)
+  input.split("\n").map do |row|
+    line = row
+    markers.each do |marker|
+      marker = '\\' + marker
+      regex = /#{marker}.*\z/
+      line.gsub!(regex, '')
+    end
+    line.strip
+  end.join("\n")
+end
+
+p solution("apples, plums % and bananas\npears\noranges !applesauce", ["%", "!"])

4kyuSudokuSolutionValidator.rb

@@ -0,0 +1,31 @@
+def validSolution(board)
+  # check rows
+  valid = board.all? { |row| row.uniq.size == row.size }
+  return false unless valid
+
+  # check column
+  valid = board.transpose.all? { |row| row.uniq.size == row.size }
+  return false unless valid
+
+  0.step(by: 3, to: 8) do |row_idx|
+    0.step(by: 3, to: 8).each do |col_idx|
+      temp = board[row_idx..row_idx+2].map { |row| row[col_idx..col_idx+2] }.flatten
+      valid = temp.size == temp.uniq.size
+      return false unless valid
+    end
+  end
+
+  valid
+end
+
+
+
+p validSolution([[5, 3, 4, 6, 7, 8, 9, 1, 2],
+                 [6, 7, 2, 1, 9, 5, 3, 4, 8],
+                 [1, 9, 8, 3, 4, 2, 5, 6, 7],
+                 [8, 5, 9, 7, 6, 1, 4, 2, 3],
+                 [4, 2, 6, 8, 5, 3, 7, 9, 1],
+                 [7, 1, 3, 9, 2, 4, 8, 5, 6],
+                 [9, 6, 1, 5, 3, 7, 2, 8, 4],
+                 [2, 8, 7, 4, 1, 9, 6, 3, 5],
+                 [3, 4, 5, 2, 8, 6, 1, 7, 9]])

5kyuDirectionsReduction.rb

@@ -0,0 +1,21 @@
+def dirReduc(arr)
+  s = arr.join('#')
+  new_size = s.size
+  loop do
+  	s.gsub!(/WEST#+EAST/, '')
+  	s.gsub!(/EAST#+WEST/, '')
+  	s.gsub!(/NORTH#+SOUTH/, '')
+  	s.gsub!(/SOUTH#+NORTH/, '')
+  	break if s.size == new_size
+  	new_size = s.size
+  end
+  s.split(/#+/).reject { |e| e.empty? }
+end
+
+a = ["NORTH", "SOUTH", "SOUTH", "EAST", "WEST", "NORTH", "WEST"]
+
+p dirReduc(a)
+
+u=["NORTH", "WEST", "SOUTH", "EAST"]
+
+p dirReduc(u)

5kyuIterativeRotationCipher.rb

@@ -0,0 +1,52 @@
+def encode(n, s)
+	s_arr = s.chars
+  p space_index = s_arr.size.times.select { |e| s_arr[e] == ' ' }
+  n.times do
+  	p s.gsub!(' ', '')
+  	k = n  > s.size ? n % s.size : n
+  	p s = s[-k..-1] + s[0..(-k-1)]
+  	space_index.each do |i|
+  		s = s[0...i] + ' ' + s[i..-1]
+  	end
+  	p s
+  	s = s.split(/ +/).map do |e|
+  		n.times { e = e[-1] + e[0..-2] }
+  		p e
+  		e
+  	end.join
+  	space_index.each do |i|
+  		s = s[0...i] + ' ' + s[i..-1]
+  	end
+  	p s
+  end
+  s
+end
+
+def decode(s)
+	m = /\A(\d+) (.*)\z/m.match(s)
+	n = m[1].to_i
+	s = m[2]
+	s_arr = s.chars
+  p space_index = s_arr.size.times.select { |e| s_arr[e] == ' ' }
+  n.times do
+  	s = s.split(/ +/).map do |e|
+  		n.times { e = e[1..-1] + e[0] }
+  		p e
+  		e
+  	end.join
+  	space_index.each do |i|
+  		s = s[0...i] + ' ' + s[i..-1]
+  	end
+  	p s
+
+  	p s.gsub!(' ', '')
+  	k = n  > s.size ? n % s.size : n
+  	p s = s[k..-1] + s[0..(k-1)]
+  	space_index.each do |i|
+  		s = s[0...i] + ' ' + s[i..-1]
+  	end
+  	p s
+  end
+  s
+end
+

5kyuMaximumsubarraysum.rb

@@ -0,0 +1,23 @@
+def max_sequence(arr)
+  p arr
+  return 0 if arr.empty? || arr.all?(&:negative?)
+
+  i = 0
+  i += 1 until arr[i].positive?
+  j = i
+  max_num = arr[i]
+
+  while j < arr.size
+    temp = arr[i..j].sum
+    max_num = temp if temp > max_num
+    if arr[i..j].sum < 0
+      i = j + 1
+      j = i
+    else
+      j += 1
+    end
+  end
+  max_num
+end
+
+p max_sequence([24, -20, -15, 2, -11, -18, -18, -24, 23, 12, -12, 11, 12, -23, 7, -14, -15, -10, -2, 14, 9, -9, -15, -17])

5kyuRGBToHexConversion.rb

@@ -0,0 +1,7 @@
+def rgb(r, g, b)
+  "%2s%2s%2s" % [r, g, b].map do |c|
+    c = c < 0 ? 0 : c
+    c = c > 255 ? 255 : c
+    c.to_s(16).upcase.rjust(2, "0")
+  end
+end

5kyuRot13.rb

@@ -0,0 +1,11 @@
+def rot13(string)
+  lower_dict = ('a'..'z').to_a
+  upper_dict = ('A'..'Z').to_a
+  string.chars.map do |s|
+    n = lower_dict[(lower_dict.index(s) + 13) % 26] if lower_dict.include?(s)
+    n = upper_dict[(upper_dict.index(s) + 13) % 26] if upper_dict.include?(s)
+    n || s
+  end.join
+end
+
+p rot13('test')

6kyuAretheythesame.rb

@@ -0,0 +1,7 @@
+def comp(array1, array2)
+  return false if array1.nil? || array2.nil?
+  array1.sort!
+  array2.sort!
+  return false if array1.size != array2.size
+  (0..(array1.size-1)).all? { |i| array2[i] == array1[i] ** 2 }
+end

6kyuCountthesmileyfaces.rb

@@ -0,0 +1,3 @@
+def count_smileys(arr)
+  arr.count { |e| /[:;][-~]?[\)D]/ =~ e }
+end