常见排序算法-Python实现

#coding=utf-8 
def binary_search(input_array, value): 
 """Your code goes here.""" 
    length = len(input_array) 
    left = 0 
    right = length-1 
 if length == 1: 
 return 0 if value == input_value[0] else -1 
 else: 
        mid = (left+right)/2 
 while(right-left>1): 
 if input_array[mid] == value: 
 return mid 
 elif input_array[mid] > value: 
                right = mid 
                mid = (left+right)/2 
 else: 
                left = mid 
                mid = (left+right)/2 
 if input_array[left] == value: 
 return left 
 elif input_array[right] == value: 
 return right 
 else: 
 return -1 
 
test_list = [1,3,9,11,15,19,29] 
test_val1 = 25 
test_val2 = 15 
print (binary_search(test_list, test_val1)) 
print (binary_search(test_list, test_val2)) 

#coding=utf-8 
 
# way=1递增排序 way=0递减排序 
def bubble_sort(array,way=1): 
	length = len(array) 
 
 if not length: 
		print("Error!The length of array must be greater than 0.\n") 
 return 'Wrong array' 
 
 if way == 1: 
 while length > 0: 
 for i in range(length-1): 
 if array[i] > array[i+1]: 
					array[i],array[i+1] = array[i+1],array[i] 
			length -= 1 
 return array 
 
 elif way == 0: 
 while length > 0: 
 for i in range(length-1): 
 if array[i] < array[i+1]: 
					array[i],array[i+1] = array[i+1],array[i] 
			length -= 1 
 return array 
 
# 加入排序判断标志，可提高运行效率 
# way=1递增排序 way=0递减排序 
def better_bubble_sort(array,way=1): 
	is_sorted = True # 判断记录上次遍历是否进行过交换，若没有则表示不用再遍历了 
	length = len(array) 
 
 if not length: 
		print("Error!The length of array must be greater than 0.\n") 
 return 'Wrong array' 
 
 if way == 1: 
 while length > 0 and is_sorted: 
 for i in range(length-1): 
				is_sorted = False 
 if array[i] > array[i+1]: 
					array[i],array[i+1] = array[i+1],array[i] 
					is_sorted = True 
			length -= 1 
 return array 
 
 elif way == 0: 
 while length > 0 and is_sorted: 
 for i in range(length-1): 
				is_sorted = False 
 if array[i] < array[i+1]: 
					array[i],array[i+1] = array[i+1],array[i] 
					is_sorted = True 
			length -= 1 
 return array 
 
 
test =  [21, 4, 1, 3, 9, 20, 25, 6, 21, 14]  
print(better_bubble_sort(test,1)) 

#coding=utf-8 
 
def insert_sort(array): 
	length = len(array) 
	flag = array[0] 
 for x in range(1,length): 
 # 之前的 
 if array[x] < array[x-1]: 
			flag = array[x] 
			y = x 
 while y != 0 and array[y-1] > flag : 
				array[y] = array[y-1] 
				y -= 1 
			array[y] = flag 
 return array 
 
test = [21, 4, 1, 3, 9, 20, 25, 20, 3] 
print(insert_sort(test)) 

#coding=utf-8 
 
def merge_sort(array): 
 if len(array) <= 1: 
 return array 
 
	split_index = len(array)/2 
	left = merge_sort(array[:split_index]) 
	right = merge_sort(array[split_index:]) 
 return merge(left,right) 
 
def merge(left,right): 
	i = 0 
	j = 0 
	result = [] 
 while i < len(left) and j < len(right): 
 if left[i] <= right[j]: 
			result.append(left[i]) 
			i += 1 
 else: 
			result.append(right[j]) 
			j += 1 
 
	result += (left[i:]) 
	result += (right[j:]) 
 return result 
 
a = [1,2] 
test = [21, 4, 1, 3, 9, 20, 25]  
print(merge_sort(test)) 

#coding=utf-8 
 
def select_sort(array): 
	length = len(array) 
 # mini = array[0] 
 for i in range(length): 
		mini = array[i] 
 for j in range(i,length): 
 if array[j] < mini: 
				mini = array[j] 
				array[i],array[j] = array[j],array[i] 
 return array 
 
test = [21, 4, 1, 3, 9, 20, 25, 20, 3]  
print(select_sort(test)) 

#coding=utf-8 
 
# 递归 
def quick_sort(lists, left, right): 
 # 快速排序 
 if left >= right: 
 return lists 
    key = lists[left] 
    low = left 
    high = right 
 while left < right: 
 while left < right and lists[right] >= key: 
            right -= 1 
        lists[left] = lists[right] 
 while left < right and lists[left] <= key: 
            left += 1 
        lists[right] = lists[left] 
    lists[right] = key 
    quick_sort(lists, low, left - 1) 
    quick_sort(lists, left + 1, high) 
 return lists 
 
 
test = [21, 4, 1, 3, 9, 20, 25, 6, 21, 14] 
print (quick_sort(test,0,len(test)-1))