problem
225. Implement Stack using Queues
code
class MyStack { public: std::queue<int> myqueue; /** Initialize your data structure here. */ MyStack() { } /** Push element x onto stack. */ void push(int x) { myqueue.push(x); for(int i=0; i<myqueue.size()-1; i++) { myqueue.push(myqueue.front()); myqueue.pop(); } } /** Removes the element on top of the stack and returns that element. */ int pop() { int b = myqueue.front(); myqueue.pop(); return b; } /** Get the top element. */ int top() { return myqueue.front();// } /** Returns whether the stack is empty. */ bool empty() { return myqueue.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(); */
注意,能够理解并熟悉堆栈stack和队列queue的性质,熟练使用stack和queue。堆栈是先进后出,队列是先进先出。
re
1. leetcode_Implement Stack using Queues;
end