CountingSort.java

package test;

public class CountingSort {
	public static void main(String[] args) {
		int[] array = new int[100];
		int[] count = new int[31];
		int[] result = new int[100];
		
		for(int i = 0 ; i < array.length ; i++) {
			array[i] = (int)(Math.random() * 31);
			count[array[i]]++;
		}

		for(int i = 1 ; i < count.length ; i++) {
			count[i] += count[i-1];
		}
		
		for(int i = array.length - 1 ; i >= 0 ; i--) {
			int value = array[i];
			count[value]--;
			result[count[value]] = value;
		}

		System.out.println("array[]");
		printArray(array);
		
		System.out.println("count[]");
		printArray(count);
		
		System.out.println("result[]");
		printArray(result);
	}
	
	private static void printArray(int[] arr) {
		StringBuilder sb = new StringBuilder();
		for(int i = 0 ; i < arr.length ; i++) {
			if(i != 0 && i % 10 == 0) {
				sb.append("\n");
			}
			sb.append(arr[i]).append("\t");
		}
		System.out.println(sb.append("\n").toString());
	}
}