diff --git a/lib/exercises.rb b/lib/exercises.rb
index e1b3850..2a7d1df 100644
--- a/lib/exercises.rb
+++ b/lib/exercises.rb
@@ -1,19 +1,44 @@
 
 # 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 * klog(k))
+# Space Complexity: O(n)
 
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  hash_map = {}
+  
+  strings.each do |str| #n
+    chars = str.chars   #k length of string
+    sorted = chars.sort # k log(k)
+    hash_map[sorted] ? hash_map[sorted].push(str) : hash_map[sorted] = [].push(str)
+  end
+ 
+  return hash_map.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!"
+  k_freq = []
+  return k_freq if list.empty?
+    
+  hash_map = Hash.new
+
+  list.each do |element| 
+    hash_map[element] ? hash_map[element] += 1 : hash_map[element] = 1
+  end
+    
+  vals = hash_map.values 
+  max_vals = vals.max(k) 
+  
+  max_vals.each do |val| 
+    key = hash_map.key(val)
+    k_freq << key
+    hash_map.delete(key)
+  end
+  return k_freq
 end
 
 
@@ -25,5 +50,46 @@ def top_k_frequent_elements(list, k)
 # Time Complexity: ?
 # Space Complexity: ?
 def valid_sudoku(table)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  table.each do |row|
+    row_map = {}
+    row.each do |elem|
+      if elem != '.'
+        if row_map[elem] 
+          return false
+        else
+          row_map[elem] = 1
+        end
+      end
+    end
+ end
+ 
+ i = 0
+ 9.times do
+    column_map = {}
+    table.each do |row|
+        col = row[i]
+        if col != '.'
+              if column_map[col] 
+                  return false
+              else
+                  column_map[col] = 1
+              end
+        end
+
+    end
+    k += 1
+ end
+ 
+ i = 0
+ k = 0
+ 9.times do
+    box_map = {}
+    while i < i + 3
+      while k < k + 3
+          
+      end
+    end 
+ end
+ 
+ return true
 end