Bubble sort using two Stacks - GeeksforGeeks

29 Jun, 2021
Prerequisite : Bubble Sort Write a function that sort an array of integers using stacks and also uses bubble sort paradigm.
Algorithm:  
1. Push all elements of array in 1st stack

2. Run a loop for 'n' times(n is size of array)
   having the following :
   2.a. Keep on pushing elements in the 2nd 
        stack till the top of second stack is 
        smaller than element being pushed from 
        1st stack.
   2.b. If the element being pushed is smaller 
        than top of 2nd stack  then swap them
        (as in bubble sort)
   *Do above steps alternatively

TRICKY STEP: Once a stack is empty, then the 
top of the next stack will be the largest 
number so keep it at its position in array 
i.e arr[len-1-i] and then pop it from that 
stack.
C++
Java
Python3
C#
Javascript
// C++ program for bubble sort// using stack#include <bits/stdc++.h>using namespace std; // Function for bubble sort using Stackvoid bubbleSortStack(int a[], int n){    stack<int> s1;         // Push all elements of array in 1st stack    for(int i = 0; i < n; i++)    {        s1.push(a[i]);    }     stack<int> s2;     for(int i = 0; i < n; i++)    {        if (i % 2 == 0)        {            while (!s1.empty())            {                int t = s1.top();                s1.pop();                 if (s2.empty())                {                    s2.push(t);                }                 else                {                    // Swapping                    if (s2.top() > t)                    {                        int temp = s2.top();                        s2.pop();                        s2.push(t);                        s2.push(temp);                    }                    else                    {                        s2.push(t);                    }                }            }                         // Tricky step            a[n - 1 - i] = s2.top();            s2.pop();        }         else        {            while (!s2.empty())            {                int t = s2.top();                s2.pop();                 if (s1.empty())                {                    s1.push(t);                }                 else                {                    if (s1.top() > t)                    {                        int temp = s1.top();                        s1.pop();                         s1.push(t);                        s1.push(temp);                    }                     else                    {                        s1.push(t);                    }                }            }                         // Tricky step            a[n - 1 - i] = s1.top();            s1.pop();        }    }         cout << "[";    for(int i = 0; i < n; i++)    {        cout << a[i] << ", ";    }    cout << "]";} // Driver codeint main(){    int a[] = { 15, 12, 44, 2, 5, 10 };    int n = sizeof(a) / sizeof(a[0]);     bubbleSortStack(a, n);     return 0;} // This code is contributed by pawki
// Java program for bubble sort// using stack import java.util.Arrays;import java.util.Stack; public class Test{    // Method for bubble sort using Stack    static void bubbleSortStack(int arr[], int n)    {        Stack<Integer> s1 = new Stack<>();                 // Push all elements of array in 1st stack        for (int num : arr)            s1.push(num);                     Stack<Integer> s2 = new Stack<>();                 for (int i = 0; i < n; i++)        {            // alternatively            if (i % 2 == 0)            {                while (!s1.isEmpty())                {                    int t = s1.pop();                                         if (s2.isEmpty())                        s2.push(t);                                        else                    {                        if (s2.peek() > t)                        {                            // swapping                            int temp = s2.pop();                            s2.push(t);                            s2.push(temp);                        }                        else                        {                            s2.push(t);                        }                    }                }                                 // tricky step                arr[n-1-i] = s2.pop();            }                        else            {                while(!s2.isEmpty())                {                    int t = s2.pop();                                         if (s1.isEmpty())                        s1.push(t);                                         else                    {                        if (s1.peek() > t)                        {                            // swapping                            int temp = s1.pop();                                                         s1.push(t);                            s1.push(temp);                        }                        else                            s1.push(t);                    }                }                                 // tricky step                arr[n-1-i] = s1.pop();            }        }                System.out.println(Arrays.toString(arr));    }         // Driver Method    public static void main(String[] args)    {        int arr[] = {15, 12, 44, 2, 5, 10};            bubbleSortStack(arr, arr.length);    }}
# Python3 program for bubble sort# using stack # Function for bubble sort using Stackdef bubbleSortStack(a, n):    s1 = []         # Push all elements of array in 1st stack    for i in range(n):        s1.append(a[i]);    s2 = []    for i in range(n):        if (i % 2 == 0):            while (len(s1) != 0):                t = s1[-1]                s1.pop();                if(len(s2) == 0):                    s2.append(t);                                  else:                                     # Swapping                    if (s2[-1] > t):                        temp = s2[-1]                        s2.pop();                        s2.append(t);                        s2.append(temp);                                         else:                        s2.append(t);                                 # Tricky step            a[n - 1 - i] = s2[-1]            s2.pop();                  else:                     while(len(s2) != 0):                t = s2[-1]                s2.pop();                 if(len(s1) == 0):                    s1.append(t);                else:                    if (s1[-1] > t):                        temp = s1[-1]                        s1.pop();                         s1.append(t);                        s1.append(temp);                    else:                        s1.append(t);                                 # Tricky step            a[n - 1 - i] = s1[-1]            s1.pop();    print("[", end = '')    for i in range(n):        print(a[i], end = ', ')    print(']', end = '') # Driver codeif __name__=='__main__':         a = [ 15, 12, 44, 2, 5, 10 ]    n = len(a)     bubbleSortStack(a, n);         # This code is contributed by rutvik_56.
// C# program for bubble sort// using stackusing System;using System.Collections.Generic; class GFG{     // Method for bubble sort using Stackstatic void bubbleSortStack(int []arr, int n){    Stack<int> s1 = new Stack<int>();         // Push all elements of array in 1st stack    foreach (int num in arr)        s1.Push(num);             Stack<int> s2 = new Stack<int>();         for (int i = 0; i < n; i++)    {        // alternatively        if (i % 2 == 0)        {            while (s1.Count != 0)            {                int t = s1.Pop();                                 if (s2.Count == 0)                    s2.Push(t);                                else                {                    if (s2.Peek() > t)                    {                        // swapping                        int temp = s2.Pop();                        s2.Push(t);                        s2.Push(temp);                    }                    else                    {                        s2.Push(t);                    }                }            }                         // tricky step            arr[n - 1 - i] = s2.Pop();        }                else        {            while(s2.Count != 0)            {                int t = s2.Pop();                                 if (s1.Count == 0)                    s1.Push(t);                                 else                {                    if (s1.Peek() > t)                    {                        // swapping                        int temp = s1.Pop();                                                 s1.Push(t);                        s1.Push(temp);                    }                    else                        s1.Push(t);                }            }                         // tricky step            arr[n - 1 - i] = s1.Pop();        }    }        Console.WriteLine("[" + String.Join(", ", arr) + "]");} // Driver Codepublic static void Main(String[] args){    int []arr = {15, 12, 44, 2, 5, 10};        bubbleSortStack(arr, arr.Length);}} // This code is contributed by 29AjayKumar
<script> // Javascript program for bubble sort// using stack // Method for bubble sort using Stackfunction bubbleSortStack(arr, n){    let s1 = [];              // Push all elements of array in 1st stack    for(let num = 0; num < arr.length; num++)        s1.push(arr[num]);             let s2 = [];          for(let i = 0; i < n; i++)    {                 // Alternatively        if (i % 2 == 0)        {            while (s1.length != 0)            {                let t = s1.pop();                                  if (s2.length == 0)                    s2.push(t);                                   else                {                    if (s2[s2.length - 1] > t)                    {                                                 // Swapping                        let temp = s2.pop();                        s2.push(t);                        s2.push(temp);                    }                    else                    {                        s2.push(t);                    }                }            }                          // Tricky step            arr[n - 1 - i] = s2.pop();        }                   else        {            while(s2.length != 0)            {                let t = s2.pop();                                  if (s1.length == 0)                    s1.push(t);                                  else                {                    if (s1[s1.length - 1] > t)                    {                                                 // Swapping                        let temp = s1.pop();                                                  s1.push(t);                        s1.push(temp);                    }                    else                        s1.push(t);                }            }                          // Tricky step            arr[n - 1 - i] = s1.pop();        }    }           document.write((arr).join(" "));} // Driver codelet arr = [ 15, 12, 44, 2, 5, 10 ];bubbleSortStack(arr, arr.length); // This code is contributed by rag2127 </script>
Output: 
[2, 5, 10, 12, 15, 44]
This article is contributed by Gaurav Miglani and Abhishek Somani . If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. 
29AjayKumar
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rag2127
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