KS

lib/exercises.rb

@@ -1,30 +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: ?
-
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  h = {}
+  solution = []
+  strings.each do |word|
+    chars = word.split('').sort().join()
+    if !h[chars]
+       h[chars]= []
+    end
+    h[chars] << word
+    return solution
+  end
 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: ?
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
-end
+counts = {}
 
+  list.each do |single|
+    counts[single] ||= 0
+    counts[single] += 1
+  end
 
-# This method will return the true if the table is still
-#   a valid sudoku table.
-#   Each element can either be a ".", or a digit 1-9
-#   The same digit cannot appear twice or more in the same 
-#   row, column or 3x3 subgrid
-# Time Complexity: ?
-# Space Complexity: ?
-def valid_sudoku(table)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+deltas = {}
+
+  counts.keys.each do |num|
+    deltas[counts[num]] ||= []
+    deltas[counts[num]] << num
+  end
+
+remains = k
+max = deltas.keys.max
+solution = []
+
+while remains > 0 && max >=0
+  if deltas[max]
+    deltas[max].each do |num|
+      solution << num
+      remains -= 1
+      break if remains == 0
+    end
+  end
+max -= 1
+end
+return solution
 end