Python排序算法之插入排序及其优化方案详解

def insertion_sort_ver1(array):
    n=len(array)
    for right in range(1,n):
        cur=right
        while cur>0 and array[cur-1]>array[cur]:
            array[cur-1],array[cur]=array[cur],array[cur-1]
            cur-=1

import numpy as np
import time

#检查是否有序
def orderCheck(array):
    for i in range(len(array)-1):
        if array[i]>array[i+1]:
            print('排序失败')
            return
    print('排序成功')
    
def sort(sort_algorithm,ori_array):
    #先复制一份数组，再进行更改
    array = np.copy(ori_array)
    start=time.clock()
    sort_algorithm(array)
    end=time.clock()
    total_time=float(end-start)
    print(sort_algorithm.__name__+" : %0.5f" % total_time)
    orderCheck(array)

def insertion_sort_ver1(array):
    n=len(array)
    for right in range(1,n):
        cur=right
        while cur>0 and array[cur-1]>array[cur]:
            array[cur-1],array[cur]=array[cur],array[cur-1]
            cur-=1
            
array=np.random.randint(0,10000,2000,dtype=int)
sort(insertion_sort_ver1, array)

#元素交换作优化
def insertion_sort_ver2(array):
    n=len(array)
    for right in range(1,n):
        cur=right
        elem=array[cur]
        while cur>0 and array[cur-1]>elem:
            array[cur]=array[cur-1]
            cur-=1
        array[cur]=elem

def binary_search(array,target):#[left,right)左闭右开
    left=0
    right=len(array)
    while left<right:#当left<right，表明区间中还有值，否则哪怕left==right,因right不可取，区间中还是无值
        middle = (left + right) >> 1
        if target<array[middle]:
            right=middle
        elif array[middle]<target:
            left=middle+1
        else:
            return middle
    return -1

def binary_search(array,index):
    left=0
    right=index
    while left<right:
        middle=(left+right)>>1
        if array[middle]>array[index]:#大于目标，可能是插入的位置，用right保留
            right=middle
        else:#小于等于，不可能是插入位置，更新left为middle+1
            left=middle+1
    return left #最后插入的位置

#利用二分查找找到插入的点，减少了比较的次数
def insertion_sort_ver3(array):
    n=len(array)
    for right in range(1,n):
        index=binary_search(array,right)
        elem=array[right]
        for i in range(right,index,-1):
            array[i]=array[i-1]
        array[index]=elem