public class CountingSort {
public static void main(String[] args) {
int[] array = new int[]{-5, 3, 9, 1, 6, 4, 10, 2, 8, 7, 15, 3, 2};
System.out.println("Before: " + Arrays.toString(array));
sort(array);
System.out.println("After: " + Arrays.toString(array));
}
public static void sort(int[] arr) {
int len = arr.length;
int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;
for (int i = 0; i < len; i++) {
min = Math.min(min, arr[i]);
max = Math.max(max, arr[i]);
}
int[] buckets = new int[max - min + 1];
Arrays.fill(buckets, 0);
for (int i = 0; i < len; i++) {
int bktId = arr[i] - min;
buckets[bktId]++;
}
int count = 0;
for (int i = 0; i < buckets.length; i++) {
for (int j = 0; j < buckets[i]; j++) {
arr[count++] = i + min;
}
}
}
}