self.B.append(self.A.pop())returnself.B[-1]defempty(self) ->bool:returnnotself.Aandnotself.B classMyQueue:def__init__(self): self.stack1=[] self.stack2=[]defpush(self, x: int) ->None:#pushself.stack1.append(x)defpop(self) ->int:whilelen(self.stack1) !=0: self.stack2....
=NULL){// Traverse the stack and print each elementcout<<temp->data<<" ";temp=temp->next;}cout<<endl;}};intmain(){Stack stk;// Create a stack objectcout<<"Input some elements onto the stack (using linked list):\n";stk.push(6);stk.push(5);stk.push(3);stk.push(1);stk.dis...
inStack.push(x); } 复杂度分析如下: 时间复杂度:O(1)O(1) 空间复杂度:O(n)O(n),需要额外的空间用于存储队列元素 出队(pop) 在入队时,由于先入的元素处于输入栈inStack的栈底,因此,为了能够弹出栈底的元素实现出队操作,需要将输入栈inStack中的元素弹出并压入到输出栈outStack中。此时,输出栈outStack...
代码例如以下: classQueue{public:stack<int>st1;stack<int>st2;boolst1_use=1;boolst2_use=0;// Push element x to the back of queue.voidpush(intx){if(st1_use==1)st1.push(x);elseif(st2_use==1)st2.push(x);}// Removes the element from in front of queue.voidpop(void){if(st1.e...
https://leetcode.com/problems/implement-queue-using-stacks/ Constaints 1 <= x <= 9 At most 100 calls will be made to push, pop, peek, and empty. All the calls to pop and peek are valid. 1. 2. 3. 4. Idea Use one stack for pushing element, the other stack for poping element...
();}/** Returns whether the stack is empty. */publicbooleanempty(){returnqueue.isEmpty();}}/*** 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();* boolean param...
pop(st) Dequeue an element from the queue. C++ Java Python #include<bits/stdc++.h> using namespace std; class Stack { queue<int>q; public: void push(int val); void pop(); int top(); bool empty(); }; void Stack::push(int val) { int s = q.size(); q.push(val); for ...
So, while it’s possible to build a thread-safe Python stack using adeque, doing so exposes yourself to someone misusing it in the future and causing race conditions. Okay, if you’re threading, you can’t uselistfor a stack and you probably don’t want to usedequefor a stack, so ...
The top layer of this stack is concerned with application or process communication. The application layer is responsible for determining which communication protocols to use based on what type of message is transmitted. For example, the layer assigns the correct email protocols such as POP, SMTP, ...
分析:用两个Stack实现queue,这里我们在pop和peek操作是都需要更新Stack2来保证Stack2非空的。另外Stack2应该在为empty后再填充,才能保证原有的位置没有发生改变。 例如:push1 push2 ,pop1 后 stack2 应该还留下了2,此时进行push3 push4 后我们不应该将3,4push到stack2中,因为stack2中还不是空的 。如果push...