数据结构-排序算法

#直接插入排序
def insert(nums):
    for i in range(1,len(nums)):
        for j in range(i-1,-1,-1):
            if nums[j+1]<nums[j]:
                temp = nums[j]
                nums[j] = nums[j+1]
                nums[j+1] = temp
            else:
                break
    return nums
        
# 冒泡排序
def bubble_sort(nums):
    for i in range(1 , len(nums)):
        for j in range(0,len(nums) - i):
            if nums[j+1]<nums[j]:
                temp = nums[j]
                nums[j] = nums[j+1]
                nums[j+1] = temp
    return nums

# 选择排序
def select_simple(nums):
    for i in range(0,len(nums)):
        nummin = nums[i]
        for j in range(i+1,len(nums)):
            if nums[j] < nummin:
                temp = nums[j]
                nums[j] = nummin
                nummin = temp
        nums[i] = nummin
    return nums

# 希尔排序
def shell_sort(items):
    n = len(items)
    step = n // 2
    #step = 5
    while step > 0:
        for cur in range(step, n):
            i = cur
            print(i,step,items[i-step],items[i])
            while i >= step and items[i-step] > items[i]:
                print('进入while')
                items[i - step], items[i] = items[i], items[i-step]
                print('i:',i,'step:',step)
                
                i -= step  ### ?????????????
                
                print(items)
                
        step = step // 2
    return items


#归并排序
def merge(arr, l, m, r): 
    n1 = m - l + 1
    n2 = r- m 
  
    # 创建临时数组
    L = [0] * (n1)
    R = [0] * (n2)
  
    # 拷贝数据到临时数组 arrays L[] 和 R[] 
    for i in range(0 , n1): 
        L[i] = arr[l + i] 
  
    for j in range(0 , n2): 
        R[j] = arr[m + 1 + j] 
  
    # 归并临时数组到 arr[l..r] 
    i = 0     # 初始化第一个子数组的索引
    j = 0     # 初始化第二个子数组的索引
    k = l     # 初始归并子数组的索引
  
    while i < n1 and j < n2 : 
        if L[i] <= R[j]: 
            arr[k] = L[i] 
            i += 1
        else: 
            arr[k] = R[j] 
            j += 1
        k += 1
  
    # 拷贝 L[] 的保留元素
    while i < n1: 
        arr[k] = L[i] 
        i += 1
        k += 1
  
    # 拷贝 R[] 的保留元素
    while j < n2: 
        arr[k] = R[j] 
        j += 1
        k += 1
def mergeSort(arr,l,r): 
    if l < r: 
        m = int((l+(r-1))/2)
        mergeSort(arr, l, m) 
        mergeSort(arr, m+1, r) 
        merge(arr, l, m, r) 

arr = [1,5,8,7,6,4,5,8,9,11]
n = len(arr) 
print ("给定的数组") 
for i in range(n): 
    print ("%d" %arr[i]), 

mergeSort(arr,0,n-1) 
print ("\n\n排序后的数组") 
for i in range(n): 
    print ("%d" %arr[i])
    
# 快速排序
def quick_sort(a,start,end):
    if start < end:
        low , high , pivotkey = start , end , a[start]
        while(low<high):
            if(a[high] < pivotkey):
                break
            high -= 1
        #将找到的值放入a[low]    
        if(low < high):
            a[low] = a[high]
            low += 1
        #从左往右找到第一个大于pivotkey的值
        while(low<high):
            if(a[low] > pivotkey):
                break
            low += 1
        #将这个值赋给上一个留下的坑a[high]
        if (low<high):
            a[high] = a[low]
            high -= 1
        a[low] = pivotkey
        quick_sort(a , start ,low-1)
        quick_sort(a , low+1 , end)
    return a