leetcode--Min Stack

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.

class MinStack {
    Stack<Integer> stack1 = new Stack<Integer>();
	Stack<Integer> stack2 = new Stack<Integer>();
	
	public void push(int x) {	
		if(stack2.size()==0||x<stack2.peek()){
			stack2.add(x);
		}else{
			stack2.add(stack2.peek());
		}
        stack1.add(x);
    }

    public void pop() {
    	stack2.pop();
    	stack1.pop();
    }

    public int top() {  
    	return stack1.peek();
    }

    public int getMin() {
        return stack2.peek();
    }
}