当输出栈outStack为空时,执行出队操作则需要先将输入栈inStack中的元素弹出并压入输出栈。详细的步骤如图2所示。 图2:将一个元素出队 代码(Java)实现如下。 /** Removes the element from in front of queue and returns that element. */publicintpop(){if(empty()) {thrownew
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. Notes: You must use only standard operations of a stack -- which means only push to top, peek...
You must use only standard operations of a stack – which means only push to top, peek/pop from top, size, and is empty operations are valid. Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as ...
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. Notes: You must use only standard oper...
classMyQueue2{// Push element x to the back of queue.Stack<Integer>stack=newStack<>();Stack<Integer>stack2=newStack<>();publicvoidpush(intx){while(!stack2.isEmpty())stack.push(stack2.pop());stack.push(x);}// Removes the element from in front of queue.publicvoidpop(){while(!sta...
public class MyQueue { Stack<Integer> s1; Stack<Integer> s2; public MyQueue() { s1 = new Stack(); s2 = new Stack(); } /** Push element x to the back of queue. */ public void push(int x) { s1.push(x); } /** Removes the element from in front of queue and returns that...
In the above example, we have implemented the stack data structure in Java. To learn more, visit Stack Data Structure. Example 2: Implement stack using Stack class Java provides a built Stack class that can be used to implement a stack. import java.util.Stack; class Main { public static ...
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 (int i=0...
/** Push element x to the back of queue. */publicvoidpush(intx) {s1.push(x); } So what if usingpeekto get the front element of the queue at this time? Logically speaking, the front element should be 1, but ins1, 1 is pushed to the bottom of the stack. Now ...
// throws Exception if the queue is not initialized public void pushList(List<E> objs) throws Exception; } Analysis: Here we are using some basic OS and JVM primitives to implement a blocking queue. Basically it is using monitor and lock.Javaexposes those two OS primitives to programmers as...