0895

0801-0900/0895_maximum_frequency_stack.rb

@@ -0,0 +1,20 @@
+class FreqStack
+ def initialize()
+ @max_freq = 0
+ @counter = Hash.new(0)
+ @freq = Hash.new { |h, k| h[k] = [] }
+ end
+
+ def push(val)
+ @counter[val] += 1
+ @freq[@counter[val]] << val
+ @max_freq = @counter[val] if @max_freq < @counter[val]
+ end
+
+ def pop()
+ val = @freq[@max_freq].pop
+ @counter[val] -= 1
+ @max_freq -= 1 while @max_freq > 0 && @freq[@max_freq].empty?
+ val
+ end
+end