Charlotte - Space

lib/exercises.rb

@@ -1,20 +1,63 @@
 
 # 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: 0(1)
+# Space Complexity: 0(n)
 
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  return [] if strings.empty?
+  return [strings] if strings.size == 1
+
+  hash1 = {}
+
+  # this is the original str
+  strings.each do |str|
+
+    # this is the sorted str
+    word = str.split("").sort.join("")
+
+    # check hash for word 
+    # if not exist, set str as hash value
+    if hash1[word].nil? 
+      hash1[word] = [str]
+    else
+      # or shovel str as hash value
+      hash1[word] << str
+    end
+
+  end
+  return hash1.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: 0(1)
+# Space Complexity: 0(n)
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
-end
+  return [] if list.empty?
+
+  hash1 = {}
+
+  # create hash from list where same elements(key) are tallied(value)
+  list.each do |num|
+    if hash1[num]
+      hash1[num] += 1
+    else 
+      hash1[num] = 1
+    end
+
+  end
+  # sort hash by value - descending
+  sorted = hash1.sort_by { |key, value| value }.reverse
+  answer = []
+  k.times do |index|
+    answer << sorted[index].first
+  end
+
+  return answer
+
+  end # closing end for top_k_frequent_elements method
 
 
 # This method will return the true if the table is still