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Implement Queue using Stack

dev-coder answered on October 19, 2022 Popularity 10/10 Helpfulness 2/10

answer Implement Queue using Stack

related Implement Stack using Queue

Implement Queue using Stack

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/*
Description

Complete the function of push and pop and front for a queue, stack object names are S1 and S2.

Expected Time complexity is O(N) for push and O(1) for pop and front.


Input
This is a function complete problem. You just have to complete the function. The input format given below is just for your understanding.

The first line of the input contains Q, the number of queries to be executed.

Each query X is of type X = 0, X = 1 or X = 2.

Query X = 0 indicates, an element Y to be pushed into the queue.

Query X = 2 indicates, an element to be removed from the queue.

Query X = 1 indicates, an element to be peeked from the queue.


Output
For each query of type X = 1, print the value at the front of the queue.


Sample Input 1 

6
0 1
0 2
0 3
1 
2
1
Sample Output 1

1
2
*/

///-----Answer

class Queue {
    constructor()
    {
        this.S1 = new Stack()
        this.S2 = new Stack()
    }
    push(value) {
    	//write your code here..
    	while(!this.S1.isEmpty()){
    	    let x = this.S1.top()
    	    this.S1.pop()
    	    this.S2.push(x)
    	}
    	this.S1.push(value)
    		while(!this.S2.isEmpty()){
    	    let x = this.S2.top()
    	    this.S2.pop()
    	    this.S1.push(x)
    	}
    }
    pop() {
     	//write your code here..
     	this.S1.pop()
     	
    }
    front() {
    	//write your code here..
    	if(!this.S1.isEmpty()){
    	    return this.S1.top()
    	}
    }
    isEmpty() {
    	//write your code here..
    	return this.S1.isEmpty()
    }
}

Popularity 10/10 Helpfulness 2/10 Language javascript

Source: Grepper

Tags: javascript queue stack using

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Contributed on Oct 19 2022

dev-coder

0 Answers Avg Quality 2/10

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Implement Stack using Queue

Comment

/*
Description

Complete the function of push and pop and top for a stack, queue object names are Q1 and Q2.

Expected Time complexity is O(N) for push and O(1) for pop and top.


Input
This is a function complete problem. You just have to complete the function. The input format given below is just for your understanding.

The first line of the input contains Q, the number of queries to be executed.

Each query X is of type X = 0, X = 1 or X = 2.

Query X = 0 indicates, an element Y to be pushed into the stack.

Query X = 2 indicates, an element to be popped off the stack.

Query X = 1 indicates, an element to be peeked from the stack.


Output
For each query of type X = 1, print the value at the front of the queue.

Sample Input                   Sample Output
6                              3
0 1                            2
0 2
0 3
1 
2
1

*/

//-----Answer

class Stack {
    constructor()
    {
        this.Q1 = new Queue()
        this.Q2 = new Queue()
    }
    push(value) {
    	//write your code here..
    	this.Q2.push(value)
    	while(!this.Q1.isEmpty()){
    	    this.Q2.push(this.Q1.front())
    	    this.Q1.pop()
    	}
    	let Q = this.Q1
    	this.Q1=this.Q2
    	this.Q2=Q
    }
    pop() {
    	//write your code here..
    	if(this.Q1.isEmpty()){
    	    return
    	}
    	this.Q1.pop()
    }
    top() {
        //write your code here..
        return this.Q1.front()
    }
    isEmpty() {
    	//write your code here..
    	return this.Q1.length
    }
}

Popularity 10/10 Helpfulness 1/10 Language javascript

Source: Grepper

Tags: javascript j

Link to this answer
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Contributed on Oct 19 2022

dev-coder

0 Answers Avg Quality 2/10

Implement Queue using Stack

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