The sword refers to offer_ the stack containing the min function

Design a stack that supports push, pop, top, etc., and retrieves the smallest element in O(1) time.

• Push (x) – Inserts element X into the stack
• Pop () – Removes the top element of the stack
• Top () – Gets the top element on the stack
• GetMin () – Gets the smallest element on the stack

code

/** * initialize your data structure here. */
var MinStack = function() {
    this.x_stack = [];
    this.min_stack = [Infinity];
};

/ * * *@param {number} x
 * @return {void}* /
MinStack.prototype.push = function(x) {
  this.x_stack.push(x);
  this.min_stack.push(Math.min(this.min_stack[this.min_stack.length - 1], x));
};

/ * * *@return {void}* /
MinStack.prototype.pop = function() {
    this.x_stack.pop()
    this.min_stack.pop()
};

/ * * *@return {number}* /
MinStack.prototype.top = function() {
    return this.x_stack[this.x_stack.length - 1]};/ * * *@return {number}* /
MinStack.prototype.getMin = function() {
    return this.min_stack[this.min_stack.length - 1]};/** * Your MinStack object will be instantiated and called as such: * var obj = Object.create(MinStack).createNew() * obj.push(x) * obj.pop() * var param_3 = obj.top() * var param_4 = obj.getMin() */
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