StackStalk
  • Home
  • Java
    • Java Collection
    • Spring Boot Collection
  • Python
    • Python Collection
  • C++
    • C++ Collection
    • Progamming Problems
    • Algorithms
    • Data Structures
    • Design Patterns
  • General
    • Tips and Tricks

Friday, March 1, 2013

C++ Counting Sort

 March 01, 2013     Algorithms     No comments   

Counting sort is a non-comparative sorting algorithm used for sorting collection of objects using small integer key values. This article explains the counting sort with an implementation in C++.

Counting sort introduction

Counting sort works when the input is known to be withing a range. Create an array of size of input range. Go through each of the numbers in the input and increment the appropriate array value (input number is mapped as the index to array). Now overwrite the original input list with key values in the array and repeating as many times as that index counter holds.
  1. Best, Average and Worst case performance is O(N).
  2. Not a comparison sort.

Implementation of counting sort

#include <iostream>

using namespace std;

const int INPUT_SIZE = 20;
const int BUCKET_K = 10;

void print(int *input)
{
    for ( int i = 0; i < INPUT_SIZE; i++ )
        cout << input[i] << " ";
    cout << endl;
}

void countingsort(int* input)
{
    int CountArr[BUCKET_K] = { 0 };

    for (int i=0;i<INPUT_SIZE;i++)
    {
        CountArr[input[i]]++;
    }

    int outputindex=0;
    for (int j=0;j<BUCKET_K;j++)
    {
        while (CountArr[j]--)
            input[outputindex++] = j;
    }

}

int main()
{
    int input[INPUT_SIZE] = { 2, 4, 6, 4, 7, 1, 4, 9, 5, 3, 7, 2, 2, 6, 9, 3, 7, 3, 4, 4 };

    cout << "Input: ";
    print(input);
    countingsort(input);
    cout << "Output: ";
    print(input);
    return 0;
}

Output:-
Input: 2 4 6 4 7 1 4 9 5 3 7 2 2 6 9 3 7 3 4 4 
Output: 1 2 2 2 3 3 3 4 4 4 4 4 5 6 6 7 7 7 9 9 
  • Share This:  
Newer Post Older Post Home

0 comments:

Post a Comment

Follow @StackStalk
Get new posts by email:
Powered by follow.it

Popular Posts

  • Avro Producer and Consumer with Python using Confluent Kafka
    In this article, we will understand Avro a popular data serialization format in streaming data applications and develop a simple Avro Produc...
  • Monitor Spring Boot App with Micrometer and Prometheus
    Modern distributed applications typically have multiple microservices working together. Ability to monitor and manage aspects like health, m...
  • Server-Sent Events with Spring WebFlux
    In this article we will review the concepts of server-sent events and work on an example using WebFlux. Before getting into this article it ...
  • Implement caching in a Spring Boot microservice using Redis
    In this article we will explore how to use Redis as a data cache for a Spring Boot microservice using PostgreSQL as the database. Idea is to...
  • Python FastAPI microservice with Okta and OPA
    Authentication (AuthN) and Authorization (AuthZ) is a common challenge when developing microservices. In this article, we will explore how t...
  • Spring Boot with Okta and OPA
    Authentication (AuthN) and Authorization (AuthZ) is a common challenge when developing microservices. In this article, we will explore how t...
  • Getting started with Kafka in Python
    This article will provide an overview of Kafka and how to get started with Kafka in Python with a simple example. What is Kafka? ...
  • Getting started in GraphQL with Spring Boot
    In this article we will explore basic concepts on GraphQL and look at how to develop a microservice in Spring Boot with GraphQL support. ...

Copyright © StackStalk