在堆栈中搜索特定元素 [英] Searching for a particular element in a stack

问题描述

我有兴趣移植这个Python代码到C ++。作为端口的一部分，我使用< stack> 头中的 std :: stack 如何确定某个字符是否包含在 stack< char> 中？例如：

I am interested in porting this Python code to C++. As part of the port, I am using std::stack from the <stack> header. How can I determine whether some character is contained within a stack<char>? For example:

std::stack<char> myStack

if (!('y' is included in myStack)) // I know that this is wrong
{
}

推荐答案

C ++ stack 不支持随机存取，因此没有直接的方法使用 stack 来检查是否包含元素。然而，您可以创建一个堆栈的副本，​​然后连续 pop 关闭该堆栈，直到找到该元素。

The C++ stack does not support random access, so there is no direct way using a stack to check if an element is contained. You can, however, make a copy of the stack and then continuously pop off that stack until the element is found.

或者，如果你确实需要搜索 stack ，你可以考虑使用 deque 随机访问。例如，您可以在 deque 上使用 find 算法搜索元素：

Alternatively, if you do need to search the stack, you could consider instead using a deque, which does support random access. For example, you could use the find algorithm on a deque to search for an element:

find(myDeque.begin(), myDeque.end(), myValue);

如果您需要频繁搜索 stack ，考虑保留一个并行 set 以及存储与堆栈相同的元素的 stack 。这样，你可以使用 set :: find 来检查（有效地）元素是否存在。

If you need frequent searches of the stack, consider keeping a parallel set along with the stack that stores the same elements as the stack. This way, you can just use set::find to check (efficiently) whether the element exists.

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