Time - Alex

lib/exercises.rb

@@ -1,19 +1,53 @@
 
 # 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) (n being size of array)
+# Space Complexity: O(n)
 
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+
+  grouped_anagrams = Array.new()
+  hash = Hash.new()
+
+  strings.each do |word|
+    separated = word.split("").sort!
+
+    if !hash.key?(separated)
+      hash[separated] = [word]
+    else
+      hash[separated] << word 
+    end 
+  end 
+
+  hash.each do |key, value|
+    grouped_anagrams << value
+  end 
+
+  return grouped_anagrams
 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 log n)
+# Space Complexity: O(n)
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  to_me = Array.new
+  hash = {}
+  return to_me if k > list.size || list.nil? 
+
+  list.each do |value|
+    if !hash[value]
+      hash[value] = 1
+    else 
+      hash[value] += 1
+    end 
+  end 
+
+  organized = hash.sort_by {|k, value| -value}
+    k.times do |i|
+      to_me << organized[i][0]
+    end 
+    return to_me
 end