Cubesort in C++

Yasin Cakal

Cubesort is a sorting algorithm that works by recursively sorting the elements of an array into small cubes and then merging them back together. It is an efficient sorting algorithm that is particularly good at sorting small amounts of data. In this article, we will discuss how the algorithm works, its time and space complexities, and provide examples of Cubesort implemented in C++.

How Cubesort Works

Cubesort is a sorting algorithm that works by dividing an array into small cubes, sorting each cube, and then merging the cubes back together. The algorithm begins by dividing the array into small cubes of size N (where N is typically 8 or 16). The algorithm then sorts each cube using an internal sorting algorithm such as insertion sort or quicksort. Once each cube is sorted, the algorithm then merges the cubes back together using a merge sort algorithm. The result is an array that is sorted in ascending order.

Time Complexity

Cubesort has an average time complexity of O(n log n). This is because the algorithm performs an internal sorting algorithm on each cube, followed by a merge sort algorithm to merge the cubes together. The time complexity is dependent on the size of the array and the internal sorting algorithm used.

The best-case time complexity of Cubesort is O(n log n), which occurs when the array is already sorted. The worst-case time complexity of Cubesort is O(n^2), which occurs when the array is not in order.

Space Complexity

The space complexity of Cubesort is O(n), which is the same as the space complexity of the internal sorting algorithm used. This is because the algorithm does not require any additional space for the sorting process.

C++ Implementation

Now that we have an understanding of how the algorithm works and its time and space complexities, let’s take a look at an example of Cubesort implemented in C++.

#include <iostream> 
#include <algorithm>

const int CUBE_SIZE = 8;

// function to sort the cube
void cubeSort(int arr[], int n)
{
    // divide the array into cubes of size CUBE_SIZE 
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        std::sort(arr + i, arr + std::min(i + CUBE_SIZE, n));
    }
 
    // merge the cubes 
    int temp[n];
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        std::merge(arr + i, arr + std::min(i + CUBE_SIZE, n),
                   arr + std::min(i + CUBE_SIZE, n),
                   arr + std::min(i + 2*CUBE_SIZE, n),
                   temp + i);
    }
 
    // copy the result from temp[] back to arr[] 
    for (int i = 0; i < n; i++)
        arr[i] = temp[i];
}

// main function
int main()
{
    // input array
    int arr[] = {3, 6, 7, 1, 5, 2, 8, 4};
    int n = sizeof(arr) / sizeof(arr[0]);
 
    // call cubeSort
    cubeSort(arr, n);
 
    // print the sorted array
    for (int i = 0; i < n; i++)
        std::cout << arr[i] << " ";
    return 0;
}

Conclusion

Cubesort is an efficient sorting algorithm that works by recursively sorting elements of an array into small cubes and then merging them back together. The algorithm has an average time complexity of O(n log n) and a space complexity of O(n). The time complexity is dependent on the size of the array and the internal sorting algorithm used. The algorithm is particularly good at sorting small amounts of data. In this article, we discussed how Cubesort works, its time and space complexities, and provided an example of Cubesort implemented in C++.

Exercises

Write a C++ program to sort an array of integers using Cubesort.

#include <iostream> 
#include <algorithm>

const int CUBE_SIZE = 8;

// function to sort the cube
void cubeSort(int arr[], int n)
{
    // divide the array into cubes of size CUBE_SIZE 
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        std::sort(arr + i, arr + std::min(i + CUBE_SIZE, n));
    }
 
    // merge the cubes 
    int temp[n];
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        std::merge(arr + i, arr + std::min(i + CUBE_SIZE, n),
                   arr + std::min(i + CUBE_SIZE, n),
                   arr + std::min(i + 2*CUBE_SIZE, n),
                   temp + i);
    }
 
    // copy the result from temp[] back to arr[] 
    for (int i = 0; i < n; i++)
        arr[i] = temp[i];
}

// main function
int main()
{
    // input array
    int arr[] = {3, 6, 7, 1, 5, 2, 8, 4};
    int n = sizeof(arr) / sizeof(arr[0]);
 
    // call cubeSort
    cubeSort(arr, n);
 
    // print the sorted array
    for (int i = 0; i < n; i++)
        std::cout << arr[i] << " ";
    return 0;
}

Write a C++ program to find the time complexity of a Cubesort algorithm.

#include <iostream> 
#include <algorithm>

const int CUBE_SIZE = 8;

// function to calculate the time complexity of Cubesort
int cubeSortTimeComplexity(int arr[], int n)
{
    int complexity = 0;
    // divide the array into cubes of size CUBE_SIZE 
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        complexity += n * log(n);
    }
 
    // merge the cubes 
    int temp[n];
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        complexity += n * log(n);
    }
 
    return complexity;
}

// main function
int main()
{
    // input array
    int arr[] = {3, 6, 7, 1, 5, 2, 8, 4};
    int n = sizeof(arr) / sizeof(arr[0]);
 
    // call cubeSortTimeComplexity
    int complexity = cubeSortTimeComplexity(arr, n);
 
    // print the time complexity
    std::cout << "Time complexity of Cubesort is: " << complexity << std::endl;
    return 0;
}

Write a C++ program to find the space complexity of a Cubesort algorithm.

#include <iostream> 
#include <algorithm>

const int CUBE_SIZE = 8;

// function to calculate the space complexity of Cubesort
int cubeSortSpaceComplexity(int n)
{
    int complexity = 0;
    // divide the array into cubes of size CUBE_SIZE 
    complexity += n;
 
    // merge the cubes 
    int temp[n];
    complexity += n;
 
    return complexity;
}

// main function
int main()
{
    // input array
    int arr[] = {3, 6, 7, 1, 5, 2, 8, 4};
    int n = sizeof(arr) / sizeof(arr[0]);
 
    // call cubeSortSpaceComplexity
    int complexity = cubeSortSpaceComplexity(n);
 
    // print the space complexity
    std::cout << "Space complexity of Cubesort is: " << complexity << std::endl;
    return 0;
}

Write a C++ program to implement Cubesort in an array of strings.

#include <iostream> 
#include <algorithm>
#include <string>

const int CUBE_SIZE = 8;

// function to sort the cube
void cubeSort(std::string arr[], int n)
{
    // divide the array into cubes of size CUBE_SIZE 
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        std::sort(arr + i, arr + std::min(i + CUBE_SIZE, n));
    }
 
    // merge the cubes 
    std::string temp[n];
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        std::merge(arr + i, arr + std::min(i + CUBE_SIZE, n),
                   arr + std::min(i + CUBE_SIZE, n),
                   arr + std::min(i + 2*CUBE_SIZE, n),
                   temp + i);
    }
 
    // copy the result from temp[] back to arr[] 
    for (int i = 0; i < n; i++)
        arr[i] = temp[i];
}

// main function
int main()
{
    // input array
    std::string arr[] = {"c", "a", "e", "b", "d"};
    int n = sizeof(arr) / sizeof(arr[0]);
 
    // call cubeSort
    cubeSort(arr, n);
 
    // print the sorted array
    for (int i = 0; i < n; i++)
        std::cout << arr[i] << " ";
    return 0;
}

Write a C++ program to sort a two-dimensional array using Cubesort.

#include <iostream> 
#include <algorithm>

const int CUBE_SIZE = 8;

// function to sort the cube
void cubeSort(int arr[][CUBE_SIZE], int n)
{
    // divide the array into cubes of size CUBE_SIZE 
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        for (int j = 0; j < CUBE_SIZE; j++)
            std::sort(arr[i] + j, arr[i] + std::min(j + CUBE_SIZE, n));
    }
 
    // merge the cubes 
    int temp[n][CUBE_SIZE];
    for (int i = 0; i < n; i += CUBE_SIZE)
    {
        for (int j = 0; j < CUBE_SIZE; j++)
            std::merge(arr[i] + j, arr[i] + std::min(j + CUBE_SIZE, n),
                       arr[i] + std::min(j + CUBE_SIZE, n),
                       arr[i] + std::min(j + 2*CUBE_SIZE, n),
                       temp[i] + j);
    }
 
    // copy the result from temp[] back to arr[] 
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < CUBE_SIZE; j++)
            arr[i][j] = temp[i][j];
    }
}

// main function
int main()
{
    // input array
    int arr[][CUBE_SIZE] = {{3, 6, 7, 1, 5, 2, 8, 4},
                            {3, 6, 7, 1, 5, 2, 8, 4},
                            {3, 6, 7, 1, 5, 2, 8, 4}};
    int n = sizeof(arr) / sizeof(arr[0]);
 
    // call cubeSort
    cubeSort(arr, n);
 
    // print the sorted array
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < CUBE_SIZE; j++)
            std::cout << arr[i][j] << " ";
        std::cout << std::endl;
    }
    return 0;
}

Data Structures and Algorithms with C++

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