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程式語言 - LeetCode - C++ - 225. Implement Stack using Queues

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題目：


解答：

class MyStack {
private:
    queue<int> q;

public:
    MyStack() {
    }
    
    void push(int x) {
        q.push(x);

        int size = q.size();
        for (int i = 0; i < size - 1; ++i) {
            q.push(q.front());
            q.pop();
        }
    }
    
    int pop() {
        int r = q.front(); q.pop();
        return r;
    }
    
    int top() {
        return q.front();
    }
    
    bool empty() {
        return q.empty();
    }
};

/**
 * Your MyStack object will be instantiated and called as such:
 * MyStack* obj = new MyStack();
 * obj->push(x);
 * int param_2 = obj->pop();
 * int param_3 = obj->top();
 * bool param_4 = obj->empty();
 */