剑指offer_19_包含min函数的栈

privateStack<Integer> stackOne;
 private Stack<Integer> stackMin;
 // 构造方法
  public Offer_01_minNumberInStack(){
      // 初始化这俩个栈
      stackOne = new Stack<>();
      stackMin = new Stack<>();
  }
  // 推入栈
  public void push(int a) {
      stackOne.push(a);
      if (stackMin.empty()) {
          stackMin.push(a);
      } else {
       stackMin.push(stackMin.peek() > a ? a : stackMin.peek());
      }
  }
  // 弹出
  public  int pop() {
       stackMin.pop();
       return stackOne.pop();
  }
  // 获取最小得元素
  public  int getMin() {
     return stackMin.peek();
  }