Data structures contest - high level
Maximum Frequency Stack
Design a stack-like data structure to push elements to the stack and pop the most frequent element from the stack. The possible commands are:
- push n - pushes an integer n onto the top of the stack;
- pop - removes and prints the most frequent element in the stack. If there is a tie for the most frequent element, the element closest to the stack's top is removed and printed.
Each line contains a single command.
For each pop command print on a separate line the corresponding result.
Input example #1
push 4 push 5 push 4 push 6 push 7 pop push 5 pop pop
Output example #1
4 5 7
Input example #2
push 5 push 3 push 1 push 3 push 9 pop pop pop pop pop
Output example #2
3 9 1 3 5