判断是否是栈的弹出序列

解题思路：题目问出栈的顺序，那我们就直接创建一个栈，试一试顺序就行
具体思路是：先把pushV[0]压栈，然后遍历popV的序列，如果当前popV的元素和栈顶元素相同，就出栈，然后遍历下一个；否则就将pushV的其他元素压入栈。
若pushV都入栈了但popV和栈顶元素仍然不匹配，那么返回false。若能成功遍历到底，就返回true

    public bool IsPopOrder(int[] pushV, int[] popV)
    {
        Stack<int> stack = new Stack<int>();
        int p = 1;
        stack.Push(pushV[0]);
        for (int i = 0; i < popV.Length; i++)
        {
            if (popV[i] != stack.Peek() && p < pushV.Length)
            {
                while (popV[i] != stack.Peek() && p < pushV.Length)
                {
                    stack.Push(pushV[p]);
                    p++;
                }
            }
            if (p >= pushV.Length && popV[i] != stack.Peek())
            {
                return false;
            }
            if (popV[i] == stack.Peek())
            {
                stack.Pop();
            }
        }
        return true;
    }