Leetcode 225 Solution

This article provides solution to leetcode question 225 (implement-stack-using-queues)
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https://leetcode.com/problems/implement-stack-using-queues

Solution

class Stack {
    queue<int> q;

public:
    // Push element x onto stack.
    void push(int x) {
        q.push(x);
    }

    // Removes the element on top of the stack.
    void pop() {
        for (int i = 0; i < q.size() - 1; i++)
            q.push(q.front()), q.pop();

        q.pop();
    }

    // Get the top element.
    int top() {
        int val = 0;

        for (int i = 0; i < q.size(); i++)
            q.push(val = q.front()), q.pop();

        return val;
    }

    // Return whether the stack is empty.
    bool empty() {
        return q.size() == 0;
    }
};