鸡尾酒排序
鸡尾酒排序，也就是定向冒泡排序，鸡尾酒搅拌排序，搅拌排序（也可以视作选择排序的一种变形），涟漪排序，来回排序或快乐小时排序，是冒泡排序的一种变形。此算法与冒泡排序的不同处在于排序时是以双向在序列中进行排序。
| 鸡尾酒排序 | |
|---|---|
 使用鸡尾酒排序为一列数字进行排序的过程 | |
| 概况 | |
| 类别 | 排序算法 |
| 数据结构 | 数组 |
| 复杂度 | |
| 平均时间复杂度 | |
| 最坏时间复杂度 | |
| 最优时间复杂度 | |
| 最佳解 | No |
| 相关变量的定义 | |
伪代码
将一个序列由小到大进行排序：
function cocktail_sort(list, list_length){ // the first element of list has index 0
bottom = 0;
top = list_length - 1;
swapped = true;
while(swapped == true) // if no elements have been swapped, then the list is sorted
{
swapped = false;
for(i = bottom; i < top; i = i + 1)
{
if(list[i] > list[i + 1]) // test whether the two elements are in the correct order
{
swap(list[i], list[i + 1]); // let the two elements change places
swapped = true;
}
}
// decreases top the because the element with the largest value in the unsorted
// part of the list is now on the position top
top = top - 1;
for(i = top; i > bottom; i = i - 1)
{
if(list[i] < list[i - 1])
{
swap(list[i], list[i - 1]);
swapped = true;
}
}
// increases bottom because the element with the smallest value in the unsorted
// part of the list is now on the position bottom
bottom = bottom + 1;
}
}
与冒泡排序不同的地方
鸡尾酒排序等于是冒泡排序的轻微变形。不同的地方在于从低到高然后从高到低，而冒泡排序则仅从低到高去比较序列里的每个元素。他可以得到比冒泡排序稍微好一点的性能，原因是冒泡排序只从一个方向进行比对（由低到高），每次循环只移动一个项目。
以序列（2,3,4,5,1）为例，鸡尾酒排序只需要访问一次序列就可以完成排序，但如果使用冒泡排序则需要四次。但是在随机数序列的状态下，鸡尾酒排序与冒泡排序的效率与其他众多排序算法相比均比较低。
实现示例
C语言
void cocktail_sort(int arr[], int len) {
int i, left = 0, right = len - 1;
int temp;
while (left < right) {
for (i = left; i < right; i++)
if (arr[i] > arr[i + 1]) {
temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
right--;
for (i = right; i > left; i--)
if (arr[i - 1] > arr[i]) {
temp = arr[i];
arr[i] = arr[i - 1];
arr[i - 1] = temp;
}
left++;
}
}
C++
template<typename T> //整數或浮點數皆可使用,若要使用物件(class)時必須設定大於(>)的運算子功能
void cocktail_sort(T arr[], int len) {
int j, left = 0, right = len - 1;
while (left < right) {
for (j = left; j < right; j++)
if (arr[j] > arr[j + 1])
swap(arr[j], arr[j + 1]);
right--;
for (j = right; j > left; j--)
if (arr[j - 1] > arr[j])
swap(arr[j - 1], arr[j]);
left++;
}
}
Rust
fn cocktail_sort<T: PartialOrd>(arr: &mut [T]) {
let mut bottom: usize = 0;
let mut top = arr.len() - 1;
let mut swapped = true;
while swapped {
swapped = false;
for i in bottom..top {
if arr[i] > arr[i+1] {
arr.swap(i, i+1);
swapped = true;
}
}
top -= 1;
for j in ((bottom + 1)..=top).rev() {
if arr[j] < arr[j - 1] {
arr.swap(j, j - 1);
swapped = true;
}
}
bottom += 1;
}
}
JAVA
public static void cocktail_sort(int[] arr) {
int i, left = 0, right = arr.length - 1;
int temp;
while (left < right) {
for (i = left; i < right; i++)
if (arr[i] > arr[i + 1]) {
temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
right--;
for (i = right; i > left; i--)
if (arr[i - 1] > arr[i]) {
temp = arr[i];
arr[i] = arr[i - 1];
arr[i - 1] = temp;
}
left++;
}
}
JavaScript
Array.prototype.cocktail_sort = function() {
var i, left = 0, right = this.length - 1;
var temp;
while (left < right) {
for (i = left; i < right; i++)
if (this[i] > this[i + 1]) {
temp = this[i];
this[i] = this[i + 1];
this[i + 1] = temp;
}
right--;
for (i = right; i > left; i--)
if (this[i - 1] > this[i]) {
temp = this[i];
this[i] = this[i - 1];
this[i - 1] = temp;
}
left++;
}
};
PHP
function swap(&$x, &$y) {
$t = $x;
$x = $y;
$y = $t;
}
function cocktail_sort(&$arr) {//php的陣列視為基本型別，所以必須用傳參才能修改原陣列
$left = 0;
$right = count($arr) - 1;
while ($left < $right) {
for ($j = $left; $j < $right; $j++)
if ($arr[$j] > $arr[$j + 1])
swap($arr[$j], $arr[$j + 1]);
$right--;
for ($j = $right; $j > $left; $j--)
if ($arr[$j - 1] > $arr[$j])
swap($arr[$j - 1], $arr[$j]);
$left++;
}
}
Python 2.7
def cocktail_sort(l):
l_len = len(l)
for i in range(l_len, 0, -1):
rem_i_l_len = abs(i - l_len)
isNeedContinue = False
obverse_count = len(l[rem_i_l_len : i-1])
reverse_count = len(l[rem_i_l_len + 1 : i-1])
for j in range(obverse_count):
if l[j] > l[j + 1]:
l[j], l[j + 1] = l[j + 1], l[j]
isNeedContinue = True
# you can print this to observe the whole process
# print l
for j in range(reverse_count, 0, -1):
if l[j] < l[j - 1]:
l[j], l[j - 1] = l[j - 1], l[j]
isNeedContinue = True
# you can print this to observe the whole process
# print l
if isNeedContinue:
continue
else:
return
if __name__ == '__main__':
sample_list = [6,5,4,3,2,100]
cocktail_sort(sample_list)
print(sample_list)
Python 3.10
def cocktail_sort(arr: list, bottom: int = None, top: int = None):
if not bottom and not top:
bottom, top = 0, len(arr) - 1
if bottom == top or bottom > top:
return
swapped: bool = False
for i in range(bottom, top):
if arr[i] > arr[i + 1]:
arr[i + 1], arr[i] = arr[i], arr[i + 1]
swapped = True
for i in range(top - 1, bottom, -1):
if arr[i] < arr[i - 1]:
arr[i - 1], arr[i] = arr[i], arr[i - 1]
swapped = True
if not swapped:
return
cocktail_sort(arr, bottom + 1, top - 1)
if __name__ == '__main__':
sample_list = [3, 7, 5, 1, 6, 4, 8, 2]
cocktail_sort(sample_list)
print(sample_list)
Golang
func cocktailSort(arr []int) {
left := 0
right := len(arr) - 1
for left < right {
for i := left; i < right; i++ {
if arr[i] > arr[i+1] {
arr[i], arr[i+1] = arr[i+1], arr[i]
}
}
right--
for i := right; i > left; i-- {
if arr[i-1] > arr[i] {
arr[i-1], arr[i] = arr[i], arr[i-1]
}
}
left++
}
}
Julia (编程语言)
# Julia Sample : CocktailSort
function CocktailSort(A)
isordered, lo, hi = false, 1, length(A)
while !isordered && hi > lo
isordered = true
for i=lo+1:hi
if A[i] < A[i-1]
A[i-1], A[i] = A[i], A[i-1]
isordered = false
end
end
hi -= 1
if isordered || hi ≤ lo
break
end
for i in hi:-1:lo+1
if A[i-1] > A[i]
A[i-1], A[i] = A[i], A[i-1]
isordered = false
end
end
lo += 1
end
return A
end
# Main Code
A = [16,586,1,31,354,43,3]
println(A) # Original Array
println(CocktailSort(A)) # Cocktail Sort Array
复杂度
鸡尾酒排序最糟或是平均所花费的次数都是 ，但如果序列在一开始已经大部分排序过的话，会接近 。