【每日一题-6】栈和队列与替换空格

两个栈实现一队列

class Queue
{
	void Push(int data)
	{
		inStack.push(data);
	}

	int Pop()
	{
		if (inStack.empty() && outStack.size())
			return -1;
		if (!outStack.empty())
		{
			while (!inStack.empty())
			{
				outStack.push(inStack.top());
				inStack.pop();
			}
			int top = outStack.top();
			outStack.pop();
			return ret;
		}

	}
private:
	stack<int> inStack;
	stack<int> outStack;
};

两个队列实现一个栈

class Stack
{
	void Push(int data)
	{
		inQueue.push(data);
	}

	int Pop()
	{
		while (inQueue.size() > 0)
		{
			outQueue.push(inQueue.front());
			inQueue.pop();
		}
		int Front = outQueue.front();
		outQueue.pop();
		return Front;
	}
protected:
	queue<int> inQueue;
	queue<int> outQueue;
};

空格替换

void ReplaceBlack(char* str,size_t n)
{
	if (str == NULL)
		return;
	int count = 0;
	for (size_t i = 0; i < n; i++)
	{
		if (*str == ' ')
			++count;
		++str;
	}
	int newLen = count * 2 + n;
	while (n >= 0 && newLen > n)
	{
		if (str[n - 1] == ' ')
		{
			str[newLen--] = '$';
			str[newLen--] = '$';
			str[newLen--] = '$';
		}
		else
		{
			str[newLen--] = str[n--];
		}
	}
}