Space - Stephanie

lib/exercises.rb

@@ -1,19 +1,48 @@
 
 # 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 the quantity of strings 
+# Space Complexity: O(1) bc we are only creating one new hash
 
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  letter_hash = {}
+
+  strings.each do |word|
+    if letter_hash[word.split("").sort] == nil 
+      letter_hash[word.split("").sort] = [word]
+    else 
+      letter_hash[word.split("").sort] << word
+    end  
+  end 
+
+  return letter_hash.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 log n)
+# Space Complexity: O(n)
+# not sure why this one is failing a test bc it returns the correct response in repl??
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  return [] if list == []
+  hash = {}
+
+  list.each do |num|
+    if hash[num]
+      hash[num] += 1
+    else
+      hash[num] = 1
+    end
+  end
+
+  sorted = hash.sort_by{|num, frequency| -frequency} 
+
+  result = []
+  k.times do |key, value|
+    result << sorted[key][0]
+  end 
+
+  return result
 end