diff --git a/lib/exercises.rb b/lib/exercises.rb
index 2cb2bfa..fc2c9c2 100644
--- a/lib/exercises.rb
+++ b/lib/exercises.rb
@@ -2,29 +2,60 @@
 
 # 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!"
+  return strings if strings.length == 0
+  hash = Hash.new()
+  strings.each do |word|
+    word_array = word.split("").sort
+    if hash.include?(word_array)
+      hash[word_array] << word
+    else
+      hash[word_array] = [word]
+    end
+  end
+
+  result = []
+  hash.each do |key, value|
+    result << value
+  end
+  return result
 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!"
-end
+  hash = Hash.new
+
+  list.each do |element|
+    if hash.include?(element)
+      hash[element] += 1
+    else
+      hash[element] = 1
+    end
+  end
+
+  hash.sort_by { |k, v| v }
+  top_k = []
 
+  hash.each do |k, v|
+    top_k << k
+  end
+
+  return top_k[0..(k - 1)]
+end
 
 # This method will return the true if the table is still
 #   a valid sudoku table.
 #   Each element can either be a ".", or a digit 1-9
-#   The same digit cannot appear twice or more in the same 
+#   The same digit cannot appear twice or more in the same
 #   row, column or 3x3 subgrid
 # Time Complexity: ?
 # Space Complexity: ?
 def valid_sudoku(table)
   raise NotImplementedError, "Method hasn't been implemented yet!"
-end
\ No newline at end of file
+end
diff --git a/test/exercises_test.rb b/test/exercises_test.rb
index a649110..1c77bae 100644
--- a/test/exercises_test.rb
+++ b/test/exercises_test.rb
@@ -5,7 +5,7 @@
     it "will return [] for an empty array" do
       #Arrange
       list = []
-      
+
       # Act-Assert
       expect(grouped_anagrams(list)).must_equal []
     end
@@ -18,9 +18,9 @@
       answer = grouped_anagrams(list)
 
       expected_answer = [
-        ["ate","eat","tea"],
-        ["nat","tan"],
-        ["bat"]
+        ["ate", "eat", "tea"],
+        ["nat", "tan"],
+        ["bat"],
       ]
 
       # Assert
@@ -42,7 +42,7 @@
         ["tar"],
         ["pop"],
         ["pan"],
-        ["pap"]
+        ["pap"],
       ]
 
       # Assert
@@ -59,7 +59,7 @@
       answer = grouped_anagrams(list)
 
       expected_answer = [
-        [ "aet", "ate", "eat", "eta", "tae", "tea"]
+        ["aet", "ate", "eat", "eta", "tae", "tea"],
       ]
       # Assert
       answer.each_with_index do |array, index|
@@ -68,17 +68,17 @@
     end
   end
 
-  xdescribe "top_k_frequent_elements" do
+  describe "top_k_frequent_elements" do
     it "works with example 1" do
       # Arrange
-      list = [1,1,1,2,2,3]
+      list = [1, 1, 1, 2, 2, 3]
       k = 2
 
       # Act
       answer = top_k_frequent_elements(list, k)
 
       # Assert
-      expect(answer.sort).must_equal [1,2]
+      expect(answer.sort).must_equal [1, 2]
     end
 
     it "works with example 2" do
@@ -128,22 +128,21 @@
       # Assert
       expect(answer.sort).must_equal [1]
     end
-
   end
 
   xdescribe "valid sudoku" do
     it "works for the table given in the README" do
       # Arrange
       table = [
-        ["5","3",".",".","7",".",".",".","."],
-        ["6",".",".","1","9","5",".",".","."],
-        [".","9","8",".",".",".",".","6","."],
-        ["8",".",".",".","6",".",".",".","3"],
-        ["4",".",".","8",".","3",".",".","1"],
-        ["7",".",".",".","2",".",".",".","6"],
-        [".","6",".",".",".",".","2","8","."],
-        [".",".",".","4","1","9",".",".","5"],
-        [".",".",".",".","8",".",".","7","9"]
+        ["5", "3", ".", ".", "7", ".", ".", ".", "."],
+        ["6", ".", ".", "1", "9", "5", ".", ".", "."],
+        [".", "9", "8", ".", ".", ".", ".", "6", "."],
+        ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+        ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+        ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+        [".", "6", ".", ".", ".", ".", "2", "8", "."],
+        [".", ".", ".", "4", "1", "9", ".", ".", "5"],
+        [".", ".", ".", ".", "8", ".", ".", "7", "9"],
       ]
 
       # Act
@@ -156,15 +155,15 @@
     it "fails for the table given in the README" do
       # Arrange
       table = [
-        ["8","3",".",".","7",".",".",".","."],
-        ["6",".",".","1","9","5",".",".","."],
-        [".","9","8",".",".",".",".","6","."],
-        ["8",".",".",".","6",".",".",".","3"],
-        ["4",".",".","8",".","3",".",".","1"],
-        ["7",".",".",".","2",".",".",".","6"],
-        [".","6",".",".",".",".","2","8","."],
-        [".",".",".","4","1","9",".",".","5"],
-        [".",".",".",".","8",".",".","7","9"]
+        ["8", "3", ".", ".", "7", ".", ".", ".", "."],
+        ["6", ".", ".", "1", "9", "5", ".", ".", "."],
+        [".", "9", "8", ".", ".", ".", ".", "6", "."],
+        ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+        ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+        ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+        [".", "6", ".", ".", ".", ".", "2", "8", "."],
+        [".", ".", ".", "4", "1", "9", ".", ".", "5"],
+        [".", ".", ".", ".", "8", ".", ".", "7", "9"],
       ]
 
       # Act
@@ -177,15 +176,15 @@
     it "fails for a duplicate number in a sub-box" do
       # Arrange
       table = [
-        ["5","3",".",".","7",".",".",".","."],
-        ["6",".","3","1","9","5",".",".","."],
-        [".","9","8",".",".",".",".","6","."],
-        ["8",".",".",".","6",".",".",".","3"],
-        ["4",".",".","8",".","3",".",".","1"],
-        ["7",".",".",".","2",".",".",".","6"],
-        [".","6",".",".",".",".","2","8","."],
-        [".",".",".","4","1","9",".",".","5"],
-        [".",".",".",".","8",".",".","7","9"]
+        ["5", "3", ".", ".", "7", ".", ".", ".", "."],
+        ["6", ".", "3", "1", "9", "5", ".", ".", "."],
+        [".", "9", "8", ".", ".", ".", ".", "6", "."],
+        ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+        ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+        ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+        [".", "6", ".", ".", ".", ".", "2", "8", "."],
+        [".", ".", ".", "4", "1", "9", ".", ".", "5"],
+        [".", ".", ".", ".", "8", ".", ".", "7", "9"],
       ]
 
       # Act
@@ -198,15 +197,15 @@
     it "fails for a duplicate number in a bottom right sub-box" do
       # Arrange
       table = [
-        ["5","3",".",".","7",".",".",".","."],
-        ["6",".","2","1","9","5",".",".","."],
-        [".","9","8",".",".",".",".","6","."],
-        ["8",".",".",".","6",".",".",".","3"],
-        ["4",".",".","8",".","3",".",".","1"],
-        ["7",".",".",".","2",".",".",".","6"],
-        [".","6",".",".",".",".","2","8","."],
-        [".",".",".","4","1","9","8",".","5"],
-        [".",".",".",".","8",".",".","7","9"]
+        ["5", "3", ".", ".", "7", ".", ".", ".", "."],
+        ["6", ".", "2", "1", "9", "5", ".", ".", "."],
+        [".", "9", "8", ".", ".", ".", ".", "6", "."],
+        ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+        ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+        ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+        [".", "6", ".", ".", ".", ".", "2", "8", "."],
+        [".", ".", ".", "4", "1", "9", "8", ".", "5"],
+        [".", ".", ".", ".", "8", ".", ".", "7", "9"],
       ]
 
       # Act
@@ -216,4 +215,4 @@
       expect(valid).must_equal false
     end
   end
-end
\ No newline at end of file
+end