9 wins the face questions offer two stacks queue

Question: two stack to implement a queue, the completion queue Push and Pop operations. Queue elements int.

Input: two stacks

Output: queue push and pop operations

Ideas:

When queues, pressed into stack1.

When the queue is empty it is determined whether stack2:

• If it is empty, then stack1 all elements of pop, pushed stack2,
• If not empty, a pop-up from stack2 element.

Code:

class Solution
{
public:
    void push(int node) {
        stack1.push(node);
    }

    int pop() {
        int result;
        if(!stack2.empty())
        {
            result = stack2.top();
            stack2.pop();
        }
            
        else
        {
            int temp;
            while(!stack1.empty())
            {
                temp = stack1.top();
                stack1.pop();
                stack2.push(temp);
            }
            if(!stack2.empty())
            {
                result=stack2.top();
                stack2.pop();
            }
            else
                return -1;
        }
        return result;
    }

private:
    stack<int> stack1;
    stack<int> stack2;
};

Complexity Analysis: time complexity of O (n), the spatial complexity is also O (n).