排序算法:
常见的排序算法有冒泡排序、选择排序、插入排序、归并排序、快速排序等
冒泡排序
def bubble_sort(arr):
n = len(arr)
for i in range(n):
for j in range(n-i-1):
if arr[j] > arr[j+1]:
arr[j], arr[j+1] = arr[j+1], arr[j]
return arr
选择排序
def selection_sort(arr):
n = len(arr)
for i in range(n):
min_idx = i
for j in range(i+1, n):
if arr[j] < arr[min_idx]:
min_idx = j
arr[i], arr[min_idx] = arr[min_idx], arr[i]
return arr
插入排序
def insertion_sort(arr):
n = len(arr)
for i in range(1, n):
key = arr[i]
j = i - 1
while j >= 0 and arr[j] > key:
arr[j+1] = arr[j]
j -= 1
arr[j+1] = key
return arr
归并排序
def merge_sort(arr):
if len(arr) > 1:
mid = len(arr) // 2
left_arr = arr[:mid]
right_arr = arr[mid:]
merge_sort(left_arr)
merge_sort(right_arr)
i = j = k = 0
while i < len(left_arr) and j < len(right_arr):
if left_arr[i] < right_arr[j]:
arr[k] = left_arr[i]
i += 1
else:
arr[k] = right_arr[j]
j += 1
k += 1
while i < len(left_arr):
arr[k] = left_arr[i]
i += 1
k += 1
while j < len(right_arr):
arr[k] = right_arr[j]
j += 1
k += 1
return arr
归并排序
def merge_sort(arr):
if len(arr) > 1:
mid = len(arr) // 2
left_arr = arr[:mid]
right_arr = arr[mid:]
merge_sort(left_arr)
merge_sort(right_arr)
i = j = k = 0
while i < len(left_arr) and j < len(right_arr):
if left_arr[i] < right_arr[j]:
arr[k] = left_arr[i]
i += 1
else:
arr[k] = right_arr[j]
j += 1
k += 1
while i < len(left_arr):
arr[k] = left_arr[i]
i += 1
k += 1
while j < len(right_arr):
arr[k] = right_arr[j]
j += 1
k += 1
return arr
快速排序
def quick_sort(arr):
if len(arr) <= 1:
return arr
else:
pivot = arr[0]
left_arr = []
right_arr = []
for i in range(1, len(arr)):
if arr[i] < pivot:
left_arr.append(arr[i])
else:
right_arr.append(arr[i])
return quick_sort(left_arr) + [pivot] + quick_sort(right_arr)