Bubble sort using two Stacks
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++
// C++ program for bubble sort // using stack #include <bits/stdc++.h>using namespace std;// Function for bubble sort using Stack void 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
// 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); } } |
C#
// C# program for bubble sort // using stack using System; using System.Collections.Generic; class GFG { // Method for bubble sort using Stack static 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 Code public static void Main(String[] args) { int []arr = {15, 12, 44, 2, 5, 10}; bubbleSortStack(arr, arr.Length); } } // This code is contributed by 29AjayKumar |
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 contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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