A Tale of Two Stacks

#include <iostream>
#include <stack>
using namespace std;

class QueueUsingStacks {
private:
    stack<int> enqueueStack;
    stack<int> dequeueStack;

    void transferToDequeueStack() {
        // Move elements from enqueueStack to dequeueStack
        while (!enqueueStack.empty()) {
            dequeueStack.push(enqueueStack.top());
            enqueueStack.pop();
        }
    }

public:
    void put(int value) {
        enqueueStack.push(value);
    }

    void pop() {
        if (dequeueStack.empty()) {
            transferToDequeueStack();
        }
        if (!dequeueStack.empty()) {
            dequeueStack.pop();
        }
    }

    int peek() {
        if (dequeueStack.empty()) {
            transferToDequeueStack();
        }
        return dequeueStack.top();
    }
};

int main() {
    int q;
    cin >> q;
    QueueUsingStacks queue;

    for (int i = 0; i < q; ++i) {
        int queryType;
        cin >> queryType;

        if (queryType == 1) {
            int value;
            cin >> value;
            queue.put(value);
        } else if (queryType == 2) {
            queue.pop();
        } else if (queryType == 3) {
            cout << queue.peek() << endl;
        }
    }

    return 0;
}