Min Stack

class MinStack {    Node head;    public void push(int x) {        if (head == null) {            head = new Node(x);        } else {            Node temp = new Node(x);            temp.min = Math.min(head.min, x);            temp.next = head;            head = temp;        }    }    public void pop() {        if (head == null) {            return;        } else {            head = head.next;        }    }    public int top() {        if (head == null) {            return Integer.MAX_VALUE;        } else {            return head.value;        }    }    public int getMin() {        if (head == null) {            return Integer.MAX_VALUE;        } else {            return head.min;        }    }}class Node {    int value;    int min;    Node next;    Node(int x) {        value = x;        min = x;        next = null;    }}