Description：

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• getMin() -- Retrieve the minimum element in the stack.

带有minimum element属性的stack操作。

class MinStack {    public Node node = null;    public void push(int x) {        if(node == null) {            node = new Node(x);            node.min = x;        }        else {            Node tNode = new Node(x);            tNode.next = node;            node = tNode;            node.min = node.next.min < x ? node.next.min : x;        }    }    public void pop() {        node = node.next;    }    public int top() {        return node.val;    }    public int getMin() {        return node.min;    }}class Node {    int val;    int min;    Node next;    public Node(int val) {        this.val = val;    }    }

 好久没1A了。