剑指Offer20

package javaOffer;

import java.util.Stack;

public class o20_getMinStack {
    Stack<Integer> stack1= new Stack<Integer>();
    Stack<Integer> stack2= new Stack<Integer>();

    public void push(int value) {
        stack1.push(value);
        if(stack2.empty())
            stack2.push(value);
        else if(value<=stack2.peek())
        {
            stack2.push(value);
        }
    }

    public void pop() {
        if(stack1.peek()==stack2.peek())
            stack2.pop();
        stack1.pop();

    }

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