计数排序（Counting sort）
*：http://en.wikipedia.org/wiki/Counting_sort
时间复杂度：O(n)
技术排序的基本思想：对每一个输入元素 x ，确定小于 x 的元素个数。利用这一信息，就可以直接把 x 放到它在输出数组中的位置上了。
伪码：
COUNTING-SORT（A, B, k）
let C[0 .. k] be a new array
for i = 0 to k
C[i] = 0
for j = 1 to A.length
C[A[j]] = C[A[j]] + 1
// C[i] now contains the number of elements equal to i.
for i = 1 to k
C[i] = C[i] + C[i - 1]
// C[i] now contains the number of elements less than or equal to i.
for j = A. length downto 1
B[C[A[j]]] = A[j]
C[A[j]] = C[A[j]] - 1
基数排序（Radix sort）
*：http://en.wikipedia.org/wiki/Radix_sort
最差时间复杂度:O(k n)，其中k为位数
基数排序分类：LSD（Least Significant Digital）和MSD（Most Signifacant Digital）
LSD伪码：
RADIX-SORT(A, d)
for i = 1 to d
use a stable sort to sort array A on digit i
桶排序（Bucket sort）
*：http://en.wikipedia.org/wiki/Bucket_sort
平均时间复杂度：O(n)
Bucket sort works as follows:
- Set up an array of initially empty "buckets."
- Scatter: Go over the original array, putting each object in its bucket.
- Sort each non-empty bucket.
- Gather: Visit the buckets in order and put all elements back into the original array.
伪码：
BUCKET-SORT(A)
n = A.length
let B[0 .. n - 1] be a new array
for i = 0 to n - 1
make B[i] an empty list
for i = 1 to n
insert A[i] into list B[nA[i]]
for i = 0 to n -1
sort list B[i] with insertion sort
concatenate the list B[0], B[1], ..., B[n -1] together in order