Space - Faezeh

lib/exercises.rb

@@ -1,19 +1,60 @@
 
 # This method will return an array of arrays.
 # Each subarray will have strings which are anagrams of each other
-# Time Complexity: ?
-# Space Complexity: ?
-
+# Time Complexity: O(n)
+# Space Complexity: O(n)
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  # create an anagrams hash of arrays
+  anagrams = {}
+  # for each string, split the characters and sort them
+  # join the characers, and test the hash keys
+  # if the key already exists add it to the array of that key
+  # if not create one
+  strings.each do |word| 
+    sorted_word = word.split(//).sort.join
+    if anagrams[sorted_word]
+      anagrams[sorted_word] << word
+    else
+      anagrams[sorted_word] = [word]
+    end
+  end
+
+  # return the arrays
+  anagrams.values
 end
 
 # This method will return the k most common elements
 # in the case of a tie it will select the first occuring element.
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n)
+# Space Complexity: O(n)
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  # create a counter hash for the numbers
+  counter = {}
+  # go through the list of numbers
+  # test the hash keys, if it is not there, add it with a number 1 value
+  # otherwise increment the value by 1
+  list.each do |num|
+    if !counter[num]
+      counter[num] = 1
+    else
+      counter[num] += 1
+    end
+  end
+
+  # list.each do |element|
+  #   counts[element] ||= 0
+  #   counts[element] += 1
+  # end
+
+  # find the K max counts
+  highest_counts = counter.values.max(k)
+  # return the values of those keys
+  most_frequent = []
+  highest_counts.each do |n|
+    most_frequent << counter.key(n)
+    counter.delete(counter.key(n))
+  end
+  return most_frequent
 end
 
 
@@ -24,6 +65,83 @@ def top_k_frequent_elements(list, k)
 #   row, column or 3x3 subgrid
 # Time Complexity: ?
 # Space Complexity: ?
+def get_valid_digit_count
+  return {
+    1 => 1,
+    2 => 1,
+    3 => 1,
+    4 => 1,
+    5 => 1,
+    6 => 1,
+    7 => 1,
+    8 => 1,
+    9 => 1,
+  }
+end
+
+def check_subgrid(table, subgrid)
+  current_row = subgrid[0]
+  current_col = subgrid[1]
+  digit_count = get_valid_digit_count
+  begin
+
+  while current_row < subgrid[0] + 3
+    while current_col < subgrid[1] + 3
+      if table[current_row][current_col] =~ /\d/
+        digit_count[ table[current_row][current_col].to_i ] -= 1
+      end
+
+      current_col += 1
+    end
+    current_col = subgrid[1]
+    current_row += 1
+  end
+  rescue NoMethodError
+    return false
+  end
+
+  return !digit_count.values.any? { |value| value < 0 }
+end
+
 def valid_sudoku(table)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  row_count = get_valid_digit_count
+  col_count = get_valid_digit_count
+
+  begin 
+    (0...table.length).each do |i|
+      row_count = get_valid_digit_count
+      col_count = get_valid_digit_count
+      (0...table.length).each do |j|
+        if table[i][j] =~ /\d/
+          row_count[ table[i][j].to_i  ] -= 1
+        end
+
+        if table[j][i] =~ /\d/
+          col_count[ table [j][i].to_i ] -= 1
+        end
+      end
+      if row_count.values.any? { |value| value < 0 }
+        return false
+      end
+      if col_count.values.any? { |value| value < 0 }
+
+        return false
+      end
+    end
+
+
+  rescue  NoMethodError # if the table has something not 0-9
+    return false
+  end
+
+  [[0,0], [0,3], [0,6],
+   [3,0], [3,3], [3,6],
+   [6,0], [6,3], [6,6]].each do |grid|
+    if !check_subgrid(table, grid)
+      puts "failing on #{grid}"
+      return false
+    end
+  end
+
+  return true
 end

test/exercises_test.rb

@@ -129,6 +129,14 @@
       expect(answer.sort).must_equal [1]
     end
 
+    it "will work for [3, 3, 3, 3, 3, 1, 1, 2, 2, 2]" do
+      list = [3, 3, 3, 3, 3, 1, 1, 2, 2, 2]
+      k = 2
+
+      answer = top_k_frequent_elements(list, k)
+
+      expect(answer.sort).must_equal [2, 3]
+    end
   end
 
   xdescribe "valid sudoku" do

test/test_helper.rb

@@ -6,4 +6,4 @@
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
-require_relative '../lib/exercises'
+require_relative '../lib/exercises'