Sort the given stack elements based on their modulo with K

Given a stack of integers and an integer K, the task is to sort the elements of the given stack using another stack in the increasing order of their modulo with K. If two numbers have the same remainder then the smaller number should come first.

Examples

Input: stack = {10, 3, 2, 6, 12}, K = 4
Output: 12 2 6 10 3
{12, 2, 6, 10, 3} is the required sorted order as the modulo
of these elements with K = 4 is {2, 3, 2, 2, 0}



Input: stack = {3, 4, 5, 10, 11, 1}, K = 3
Output: 3 1 4 10 5 11

Approach: An approach to sort the elements of the stack using another temporary stack has been discussed in this article, the same approach can be used here to sort the elements based on their modulo with K, the only difference is that when the elements being compared give the same modulo value then they will be compared based on their values.

Below is the implementation of the above approach:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
  
// Function to sort the stack using
// another stack based on the
// values of elements modulo k
void sortStack(stack<int>& input, int k)
{
    stack<int> tmpStack;
  
    while (!input.empty()) {
  
        // Pop out the first element
        int tmp = input.top();
        input.pop();
  
        // While temporary stack is not empty
        while (!tmpStack.empty()) {
            int tmpStackMod = tmpStack.top() % k;
            int tmpMod = tmp % k;
  
            // The top of the stack modulo k is
            // greater than (temp & k) or if they
            // are equal then compare the values
            if ((tmpStackMod > tmpMod)
                || (tmpStackMod == tmpMod
                    && tmpStack.top() > tmp)) {
  
                // Pop from temporary stack and push
                // it to the input stack
                input.push(tmpStack.top());
                tmpStack.pop();
            }
            else
                break;
        }
  
        // Push temp in tempory of stack
        tmpStack.push(tmp);
    }
  
    // Push all the elements in the original
    // stack to get the ascending order
    while (!tmpStack.empty()) {
        input.push(tmpStack.top());
        tmpStack.pop();
    }
  
    // Print the sorted elements
    while (!input.empty()) {
        cout << input.top() << " ";
        input.pop();
    }
}
  
// Driver code
int main()
{
    stack<int> input;
    input.push(10);
    input.push(3);
    input.push(2);
    input.push(6);
    input.push(12);
  
    int k = 4;
  
    sortStack(input, k);
  
    return 0;
}

chevron_right


Output:

12 2 6 10 3


My Personal Notes arrow_drop_up

An undergraduate, doing Btech Computer Engineering from Aligarh Muslim University ,Aligarh UP

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.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.