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    "Design a stack that supports push, pop, top, and retrieving the minimum\n",
    "element in constant time.\n",
    "\n",
    "  * push(x) -- Push element x onto stack.\n",
    "  * pop() -- Removes the element on top of the stack.\n",
    "  * top() -- Get the top element.\n",
    "  * getMin() -- Retrieve the minimum element in the stack.\n",
    "\n",
    "\n",
    "\n",
    "**Example 1:**\n",
    "\n",
    "\n",
    "\n",
    "    **Input**\n",
    "    [\"MinStack\",\"push\",\"push\",\"push\",\"getMin\",\"pop\",\"top\",\"getMin\"]\n",
    "    [[],[-2],[0],[-3],[],[],[],[]]\n",
    "\n",
    "    **Output**\n",
    "    [null,null,null,null,-3,null,0,-2]\n",
    "\n",
    "    **Explanation**\n",
    "    MinStack minStack = new MinStack();\n",
    "    minStack.push(-2);\n",
    "    minStack.push(0);\n",
    "    minStack.push(-3);\n",
    "    minStack.getMin(); // return -3\n",
    "    minStack.pop();\n",
    "    minStack.top();    // return 0\n",
    "    minStack.getMin(); // return -2\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "**Constraints:**\n",
    "\n",
    "  * Methods `pop`, `top` and `getMin` operations will always be called on **non-empty** stacks."
   ],
   "metadata": {}
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  {
   "outputs": [
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     "output_type": "execute_result",
     "data": {
      "text/plain": "get_min (generic function with 1 method)"
     },
     "metadata": {},
     "execution_count": 1
    }
   ],
   "cell_type": "code",
   "source": [
    "# @lc code=start\n",
    "using LeetCode\n",
    "Base.@kwdef struct MinStack{V<:Number}\n",
    "    nums::Vector{V} = Int[]\n",
    "    min_nums::Vector{V} = Int[]\n",
    "end\n",
    "\n",
    "function Base.push!(stack::MinStack, val::Int)::Nothing\n",
    "    Base.push!(stack.nums, val)\n",
    "    if isempty(stack.min_nums) || val <= stack.min_nums[end]\n",
    "        Base.push!(stack.min_nums, val)\n",
    "    end\n",
    "    return nothing\n",
    "end\n",
    "\n",
    "function Base.pop!(stack::MinStack)::Nothing\n",
    "    if Base.pop!(stack.nums) == stack.min_nums[end]\n",
    "        Base.pop!(stack.min_nums)\n",
    "    end\n",
    "    return nothing\n",
    "end\n",
    "\n",
    "top(stack::MinStack)::Int = stack.nums[end]\n",
    "\n",
    "get_min(stack::MinStack)::Int = stack.min_nums[end]\n",
    "# @lc code=end"
   ],
   "metadata": {},
   "execution_count": 1
  },
  {
   "cell_type": "markdown",
   "source": [
    "---\n",
    "\n",
    "*This notebook was generated using [Literate.jl](https://github.com/fredrikekre/Literate.jl).*"
   ],
   "metadata": {}
  }
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