232. Implement Queue using Stacks(栈实现队列) 请你仅使用两个栈实现先入先出队列。队列应当支持一般队列支持的所有操作(push、pop、peek、empty): 实现MyQueue 类: void push(int x) 将元素 x 推到队列的末尾 int pop() 从队列的开头移除并返回元素 int peek() 返回队列开头的元素 boolean empty() 如果...
}/** Push element x to the back of queue. */publicvoidpush(intx){while(!s2.empty()) { s1.push(s2.pop()); } s1.push(x); }/** Removes the element from in front of queue and returns that element. */publicintpop(){if(s2.empty()) {while(!s1.empty()) { s2.push(s1.pop(...
classMyQueue4{privateStack<Integer>stack;/** Initialize your data structure here. */publicMyQueue4(){stack=newStack<Integer>();}/** Push element x to the back of queue. */publicvoidpush(intx){stack.add(0,x);}/** Removes the element from in front of queue and returns that element....
232_queue_using_stacksBPush.png 2.题解: # 使用两个stack,一个正常放入输入值,一个在输出时候使用.classMyQueue(object):def__init__(self):self.input_stack=[]self.output_stack=[]defpush(self,x):self.input_stack.append(x)defpop(self):iflen(self.output_stack)==0:foriinrange(len(self.i...
queue.push(1); queue.push(2); queue.peek(); // returns 1 queue.pop(); // returns 1 queue.empty(); // returns false 1. 2. 3. 4. 5. 6. 7. 思路是需要用到两个栈,用first和second表示。以下分别解释一下每个函数的实现方式。
Implement Queue using Stacks 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.
Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue. pop() -- Removes the element from in front of queue. peek() -- Get the front element. empty() -- Return whether the queue is empty. ...
Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue. pop() -- Removes the element from in front of queue. peek() -- Get the front element. empty() -- Return whether the queue is empty. class MyQueue { Stack<Integer> input...
Let S1 and S2 be the two Stacks to be used in the implementation of queues. struct Stack { struct Queue *Q1; struct Queue *Q2; } We make sure that one queue is empty always. Push operation : Whichever queue is not empty, insert the element in it. Check whether queue Q1 is empty...
class QueueTwoStacks(object): # Implement the enqueue and dequeue methods def enqueue(self, item): pass def dequeue(self): pass # Tests class Test(unittest.TestCase): def test_basic_queue_operations(self): queue = QueueTwoStacks() queue.enqueue(1) queue.enqueue(2) queue.enqueue(3) actual...