Min Stack

正好前两天看 剑指offer 看到了 并且深入理解了O(∩_∩)O~

class MinStack {        Stack<Integer> rawStack = new Stack<Integer>();    Stack<Integer> minStack = new Stack<Integer>();    public void push(int x) {        rawStack.push(x);        if(minStack.empty()){            minStack.push(x);        }        else{            int min = minStack.peek();            if(x < min){                minStack.push(x);            }            else{                minStack.push(min);            }        }    }    public void pop() {        rawStack.pop();        minStack.pop();    }    public int top() {        return rawStack.peek();    }    public int getMin() {        return minStack.peek();    }}