Question

Write a radix sort that works with String objects, that sorts the strings in alphabetical order, and is case-insensitive. write a version that can do this with a set of String objects that are all of EXACTLY THE SAME LENGTH.

java

Answer 1

package Sort;

import java.util.*;

public class RedixSortString
{
/*
* Method to perform radix sort
* Parameter:
*    stringWords - Array of string contains words
*    maximumLength - maximum length of the string
* Assuming all string length is same (considering 5)
*/
public static void radixSort(String [] stringWords, int maximumLength)
{
   // Creates a constant for maximum bucket of size 256
   // for each ASCII value
final int MAXBUCKETS = 256;

// Creates an array list to store words by its length
ArrayList<String> [] wordsBasedOnLength = new ArrayList[maximumLength + 1];
  
// Creates an array list for storing words in bucket of size 256
ArrayList<String> [] bucketsForWord = new ArrayList[MAXBUCKETS];
  
// Loops till length of the words by length array list to
// create each array list
for(int index = 0; index < wordsBasedOnLength.length; index++)
   wordsBasedOnLength[index] = new ArrayList<>();
  
// Loops till maximum number of buckets to create each bucket
// to store words
for(int index = 0; index < MAXBUCKETS; index++)
   bucketsForWord[index] = new ArrayList<>( );
  
// Loops till end of the parameter stringWords string array
// Extracts each word
for(String word : stringWords)
{
   // Adds the current word to wordsBasedOnLength array list
   // at the index position of the current word length
   wordsBasedOnLength[word.length()].add(word);
}// End of for loop
  
int index = 0;
// Loops till end of the array list wordsBasedOnLength
// to extract all words
for(ArrayList<String> currentWord : wordsBasedOnLength)
{
   // Loops to get each word from currentWord array list
   for(String word : currentWord)
   {
       // Assigns the word at current index position of
       // parameter wtringWords
   stringWords[index++] = word;
   }// End of inner for loop
}// End of outer for loop
  
// Stores number of words in the parameter stringWords
int countWords = stringWords.length;
  
// Loops from end of the length to beginning based on the parameter
// maximum length of the word
for(int indexPosition = maximumLength - 1; indexPosition >= 0; indexPosition--)
{
   // Counts number of words present at current index position plus one
   // index position of the array list wordsBasedOnLength
   countWords -= wordsBasedOnLength[indexPosition + 1].size();
  
// Loops from current count words to number of words in the
   // parameter stringWords
for(int counter = countWords; counter < stringWords.length; counter++)
   // Stores the character at indexPosition of counter index position
   // of parameter stringWords and add it to bucketsForWords array list
   bucketsForWord[stringWords[counter].charAt(indexPosition)].
       add(stringWords[counter]);
// Assigns countWords value to index
index = countWords;
  
// Loops till end of the bucketForWords array list
// Extracts all words
for(ArrayList<String> currentWordInBucket : bucketsForWord)
{
   // Extracts each word from currentWordInBucket
for(String word : currentWordInBucket)
   // Adds the current word at current index position of
   // parameter stringWords
   // Increase the index counter by one
   stringWords[index++] = word;
// Clears the bucket
currentWordInBucket.clear();
}// End of inner for loop
}// End of outer for loop
}// End of method

// main method definition
public static void main(String [] ss)
{
   // Creates an object of class Random
Random random = new Random();
// Declares an array of string of size 10 to store words
String [] stringArray = new String[10];
// Defines a constant for maximum length of each word
final int MAXLEN = 5;
  
// Loops 10 times to generate 10 words
for(int wordCounter = 0; wordCounter < 10; wordCounter++)
{
   // To store the random word generated
String randomWord = "";
  
// Loops till maximum length of each word (I have taken 5)
for(int counter = 0; counter < MAXLEN; counter++)
   // Generates random character between 'A' and 'Z'
   randomWord += (char) ('A' + random.nextInt(26));
  
// Assigns the random word at wordCounter index position of
// stringArray
stringArray[wordCounter] = randomWord;
}// End of for loop
  
System.out.println("\n\n \t *********** Before Radix Sort *********** \n");
// Loops till end of the stringArray and displays each word
for(int i = 0; i < stringArray.length; i++)
   System.out.print(stringArray[i] + ", ");
  
// Calls the method to perform radix sort
radixSort(stringArray, MAXLEN);
  
System.out.println("\n\n \t *********** After Radix Sort *********** \n");
// Loops till end of the stringArray and displays each word
for(int i = 0; i < stringArray.length; i++)
   System.out.print(stringArray[i] + ", ");
}// End of main method
}// End of class

Sample Output 1:

    *********** Before Radix Sort ***********

BLMET, ACERB, CUEAQ, GVLVB, FTCGA, YGDFA, EAGFO, YOAEZ, XJGZD, NIGJW,

    *********** After Radix Sort ***********

ACERB, BLMET, CUEAQ, EAGFO, FTCGA, GVLVB, NIGJW, XJGZD, YGDFA, YOAEZ,

Sample Output 2:

    *********** Before Radix Sort ***********

IFBYM, KEPDI, YKFBP, YERTN, ZSIDJ, YZZVJ, WLIDE, NUYII, NDERN, MBGTG,

    *********** After Radix Sort ***********

IFBYM, KEPDI, MBGTG, NDERN, NUYII, WLIDE, YERTN, YKFBP, YZZVJ, ZSIDJ,