概要
算法理论讲解有专业的书籍和视频资源，本篇文章主要展示算法排序的python语言描述，具体讲解的资源地址参见文末参考引用
冒泡排序(Bubble Sort)
# 冒泡排序
def bubbleSort(seq=None, reversed=False):
lens = len(seq)
for i in range(lens):
for j in range(lens - i - 1):
if (seq[j] < seq[j + 1] if reversed else seq[i] > seq[j]):
seq[j], seq[j + 1] = seq[j + 1], seq[j]
return seq
if __name__=="__main__":
#打印结果为：[15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
print(bubbleSort([10, 1, 3, 5, 7, 9, 2, 4, 6, 8, 11, 15, 0, 12, 14, 13],True))
选择排序(Selection Sort)
# 选择排序
def selectionSort(seq=None, reversed=False):
lens = len(seq)
for i in range(lens):
min_index = i
for j in range(i + 1, lens):
if (seq[min_index] < seq[j] if reversed else seq[i] > seq[j]):
min_index = j
seq[i], seq[min_index] = seq[min_index], seq[i]
return seq
if __name__ == "__main__":
# 打印结果为：[15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
print(selectionSort([10, 1, 3, 5, 7, 9, 2, 4, 6, 8, 11, 15, 0, 12, 14, 13], True))
插入排序(Insertion Sort)
# 插入排序
def insertionSort(seq=None, reversed=False):
lens = len(seq)
for i in range(1, lens):
key = seq[i]
j = i
while j > 0 and (seq[j - 1] < seq[j] if reversed else seq[j - 1] > seq[j]):
seq[j], seq[j - 1] = seq[j - 1], seq[j]
j -= 1
return seq
if __name__ == "__main__":
# 打印结果为：[15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
print(insertionSort([10, 1, 3, 5, 7, 9, 2, 4, 6, 8, 11, 15, 0, 12, 14, 13], True))
归并排序(Selection Sort)
# 归并排序(分）
def mergeSort(seq):
if len(seq) < 2:
return seq
mid = len(seq) // 2
left = mergeSort(seq[:mid])
right = mergeSort(seq[mid:])
return merge(left, right)
# 归并排序（治）
def merge(left, right):
if not len(left) or not len(right):
return left or right
result = []
i, j = 0, 0
while (len(result) < len(left) + len(right)):
if left[i] < right[j]:
result.append(left[i])
i += 1
else:
result.append(right[j])
j += 1
if i == len(left) or j == len(right):
result.extend(left[i:] or right[j:])
break
return result
if __name__ == "__main__":
# 打印结果为：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
print(mergeSort([10, 1, 3, 5, 7, 9, 2, 4, 6, 8, 11, 15, 0, 12, 14, 13]))
快速排序(Selection Sort)
# 快速排序
def quickSort(seq, start, end):
if start < end:
split = partition(seq, start, end)
quickSort(seq, start, split - 1)
quickSort(seq, split + 1, end)
return seq
def partition(seq, start, end):
pivot_index = start - 1
for i in range(start, end):
# 选择最右边的为pivot
if seq[i] < seq[end]:
pivot_index += 1
seq[pivot_index], seq[i] = seq[i], seq[pivot_index]
seq[end], seq[pivot_index + 1] = seq[pivot_index + 1], seq[end]
return pivot_index + 1
if __name__ == "__main__":
# 打印结果为：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
print(quickSort([10, 1, 3, 5, 7, 9, 2, 4, 6, 8, 11, 15, 0, 12, 14, 13], 0, 15))
参考引用
1, sole learn，ios、android均可免费下载
2, github源文件地址
3，北大公开课 算法设计与分析 屈婉玲教授
4，数据结构-浙江大学
5，算法(普林斯顿大学)
