min-stack.ts

/**
 * initialize your data structure here.
 */
export class MinStack {
  stack: any[]
  minStack: any[]
  constructor () {
    this.stack = []
    this.minStack = [Infinity]
  }

  push (x: number): void {
    this.stack.push(x)
    this.minStack.push(Math.min(this.minStack[this.minStack.length - 1], x))
  }

  pop (): void {
    this.stack.pop()
    this.minStack.pop()
  }

  top (): number {
    return this.stack[this.stack.length - 1]
  }

  getMin (): number {
    return this.minStack[this.minStack.length - 1]
  }
}

/**
 * Your MinStack object will be instantiated and called as such:
 * var obj = new MinStack()
 * obj.push(x)
 * obj.pop()
 * var param_3 = obj.top()
 * var param_4 = obj.getMin()
 */