Sort - cardinal sort

Radix sorting ( Bucket sort ) Introduce :
Radix sorting （radix sort） Belong to “ Distributive sort ”（distribution sort）, also called “ Barrel method ”（bucket sort） or bin sort, seeing the name of a thing one thinks of its function , It is through the value of each bit of the key value , Assign elements to be sorted to some “ bucket ” in , To achieve the function of sorting
Radix sort is a sort of stability , Cardinality sorting is a stable sorting method with high efficiency
Radix sorting (Radix Sort) It's an extension of bucket sort

The basic idea of Radix sorting
Unify all values to be compared into the same digit length , A shorter digit is zeroed . then , Let's start at the lowest point , Sort them one at a time . In this way, from the lowest ranking to the completion of the highest ranking , The sequence becomes an ordered sequence .

Code implementation

import java.util.Arrays;
public class practice {
    
	public static void main(String[] args) {
    
		int[] arr = new int[] {
    12,98,100,123,1,155,26,30,87,96,130,97,65,88,79};
		sort(arr);
		System.out.println(Arrays.toString(arr));
	}
	
	public static void sort(int[] arr) {
    
		// Defining buckets 
		int[][] bucket = new int[10][arr.length];
		// Define the bucket recorder 
		int[] elementCounts = new int[10];
		
		//  Find the maximum value in the array 
		int max = arr[0];
		for(int i = 0;i<arr.length;i++) {
    
			if(arr[i] > max) {
    
				max = arr[i];
			}
		}
		
		// Find the number of digits of the maximum value 
		int maxLength = (max + "").length();
		
		int n = 1;
		for(int h = 0;h<maxLength;h++) {
    
			// Put data into the bucket 
			for(int i = 0;i<arr.length;i++){
    
				// Calculate the value of a bit 
				int element = arr[i] / n % 10;// Put into the bucket 
				int count = elementCounts[element];
				bucket[element][count] = arr[i];
				elementCounts[element] = elementCounts[element] + 1;
			}
			int index= 0;
			// Take out the data in the bucket 
			for(int k = 0;k<elementCounts.length;k++){
    
				if(elementCounts[k] !=0){
    
					for(int l = 0;l<elementCounts[k];l++){
    
						arr[index] = bucket[k][l];
						index++;
					}
				}
				// Empty the bucket recorder 
				elementCounts[k] = 0;
			}
			n = n * 10;
		}

	}	
}