java算法排序之计数排序

package 十大排序;

public class 计数排序 {

    public static void main(String[] args) {
        int[] arr={10,9,11,8,7,13,2,1,12,0,0};
        sort(arr);
        for (int i = 0; i <arr.length ; i++) {
            System.out.print(arr[i]);
            System.out.print(" ");
        }
    }

    private static void sort(int[] A) {
        int[] helper = maxOf(A);
        for (int i = 0; i < A.length; i++) {
            helper[A[i]]++;
        }

        int k = 0;
        for (int i = 0; i < helper.length; i++) {
            while (helper[i] > 0) {
                A[k++] = i;
                helper[i]--;
            }
        }

    }

    private static int[] maxOf(int[] A) {
        int max = -1;
        for (int i = 0; i < A.length; i++) {
            if (A[i] > max) {
                max = A[i];
            }
        }
        return new int[max + 1];
    }

}