155 - Benjamin Thanks

/ * 
    Method a: from 0 implemented using the stack list, to store a minimum value min. 
            Complicated place, if pop the minimum number, it is necessary to re-find the smallest number of times. 
 * / 
Public  class MinStack { 
    List <Integer> List;
     int min;
     / ** the initialize your Data Structure here Wallpaper. * / 
    Public MinStack () { 
        List = new new the LinkedList <> (); 
        min = Integer.MAX_VALUE; 
    } 

    public  void Push ( int X) {
         IF (X < min) 
            min = X; 
        List.add (X); 
    } 

    public void pop() {
        if (min==list.get(list.size()-1)){
            min=Integer.MAX_VALUE;
            for (int i=0;i<list.size()-1;i++){
                if (list.get(i)<min)
                    min=list.get(i);
            }
        }
        if (list.size()!=0)
            list.remove(list.size()-1);

    }

    public int top() {
        return list.get(list.size()-1);
    }

    public  int X) {getMin () {
         return min; 
    } 
    / * 
        Solution two: using Java stack, and with an auxiliary stack to save the minimum value. 
     * / 
    Public  class MinStack2 { 
        Stack <Integer> Stack; 
        Stack <Integer> Helper;
         / ** the initialize your Data Structure here Wallpaper. * / 
        Public MinStack2 () { 
            Stack = new new Stack <> (); 
            Helper = new new Stack <> ( ); 
        } 

        public  void Push ( int 
            stack.push (X); 
            IF (helper.isEmpty()||x<=helper.peek())
                helper.push(x);
        }

        public void pop() {
            if (!stack.isEmpty()){
                int i=stack.pop();
                if (i==helper.peek())
                    helper.pop();
            }
        }

        public int top() {
            if (!stack.isEmpty())
                return stack.peek();
            throw new RuntimeException("stack is empty");
        }

        public int getMin() {
            if (!helper.isEmpty())
                return helper.peek();
            throw new RuntimeException("stack is empty");
        }
    }

}