Fire - Gessica Mohr

lib/exercises.rb

@@ -1,19 +1,49 @@
 
 # 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!"
+  # raise NotImplementedError, "Method hasn't been implemented yet!"
+  return [] if strings.empty?
+
+  hash = Hash.new
+
+  strings.each do |word|
+    array_letters = word.split("").sort
+
+    if hash[array_letters]
+      hash[array_letters] << word
+    else
+      hash[array_letters] = [word]
+    end
+  end
+
+  return 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(nlogn)
+# Space Complexity: O(n)
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  # raise NotImplementedError, "Method hasn't been implemented yet!"
+  return [] if list.empty?
+
+  hash = Hash.new(0)
+
+  list.each do |num|
+    hash[num] += 1
+  end
+
+  sorted_hash = hash.sort_by {|key, value| -value}
+
+  return sorted_hash[0..k-1].map { |num, count| num}
+
+
 end