# ---
# title: 895. Maximum Frequency Stack
# id: problem895
# author: Tian Jun
# date: 2020-10-31
# difficulty: Hard
# categories: Hash Table, Stack
# link: <https://leetcode.com/problems/maximum-frequency-stack/description/>
# hidden: true
# ---
# 
# Implement `FreqStack`, a class which simulates the operation of a stack-like
# data structure.
# 
# `FreqStack` has two functions:
# 
#   * `push(int x)`, which pushes an integer `x` onto the stack.
#   * `pop()`, which **removes** and returns the most frequent element in the stack. 
#     * If there is a tie for most frequent element, the element closest to the top of the stack is removed and returned.
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input:
#     ["FreqStack","push","push","push","push","push","push","pop","pop","pop","pop"],
#     [[],[5],[7],[5],[7],[4],[5],[],[],[],[]]
#     Output: [null,null,null,null,null,null,null,5,7,5,4]
#     **Explanation** :
#     After making six .push operations, the stack is [5,7,5,7,4,5] from bottom to top.  Then:
#     
#     pop() -> returns 5, as 5 is the most frequent.
#     The stack becomes [5,7,5,7,4].
#     
#     pop() -> returns 7, as 5 and 7 is the most frequent, but 7 is closest to the top.
#     The stack becomes [5,7,5,4].
#     
#     pop() -> returns 5.
#     The stack becomes [5,7,4].
#     
#     pop() -> returns 4.
#     The stack becomes [5,7].
#     
# 
# 
# 
# **Note:**
# 
#   * Calls to `FreqStack.push(int x)` will be such that `0 <= x <= 10^9`.
#   * It is guaranteed that `FreqStack.pop()` won't be called if the stack has zero elements.
#   * The total number of `FreqStack.push` calls will not exceed `10000` in a single test case.
#   * The total number of `FreqStack.pop` calls will not exceed `10000` in a single test case.
#   * The total number of `FreqStack.push` and `FreqStack.pop` calls will not exceed `150000` across all test cases.
# 
# 
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
