import java.util.Arrays; public class CountingSort { public static void countingSort(int[] nums, int min, int max) { int n = nums.length; int k = max - min + 1; int[] c = new int[k]; for (int v : nums) { c[v - min]++; } for (int i = 1; i < k; i++) { c[i] += c[i - 1]; } int[] r = new int[n]; for (int i = n - 1; i >= 0; i--) { int v = nums[i]; int a = c[v - min]; r[a - 1] = v; c[v - min]--; } System.arraycopy(r, 0, nums, 0, n); } public static void main(String[] args) { // test case 1 int[] nums = {1, 2, 7, 9, 5, 5, 8}; countingSort(nums, 1, 9); System.out.println(Arrays.toString(nums)); // test case 2 int[] nums2 = {2, 7, 9, 5, 5, 8}; countingSort(nums2, 2, 9); System.out.println(Arrays.toString(nums2)); } }