介紹
插入排序的工作原理是，對於每個未排序數據，在已排序序列中從後向前掃描，找到相應位置並插入。
步驟
- 從第一個元素開始，該元素可以認爲已經被排序
- 取出下一個元素，在已經排序的元素序列中從後向前掃描
- 如果被掃描的元素（已排序）大於新元素，將該元素後移一位
- 重複步驟3，直到找到已排序的元素小於或者等於新元素的位置
- 將新元素插入到該位置後
- 重複步驟2~5
代碼
# -*- coding: utf-8 -*-
"""
Created on Wed Apr 27 10:41:00 2016
@author: zang
"""
from matplotlib import pyplot as plt
import random
def bubbleSort1(unsortedList):#採用遞歸
if len(unsortedList)<2:
return unsortedList
list_length=len(unsortedList)
for i in range(list_length - 1):
if unsortedList[i] > unsortedList[i + 1]:
unsortedList[i],unsortedList[i + 1] = unsortedList[i + 1], unsortedList[i]
max_num = unsortedList.pop()
return bubbleSort1(unsortedList) + [max_num]
def insertSort(unsortedList):
n = len(unsortedList)
for i in range(1,n):
if unsortedList[i] < unsortedList[i-1]:
temp = unsortedList[i]
index = i #待插入的下標
for j in range(i-1,-1,-1): #從i-1 循環到 0 (包括0)
if unsortedList[j] > temp :
unsortedList[j+1] = unsortedList[j]
index = j #記錄待插入下標
else :
break
unsortedList[index] = temp
return unsortedList
def plotScatter(inputList):
plt.scatter(range(len(inputList)),inputList)
plt.show()
if __name__ == "__main__":
num_list = range(1000)
unsortedList = random.sample(num_list, 30)
print "unsortedList:"
plotScatter(unsortedList)
print unsortedList
sortedList = insertSort(unsortedList)
print "sortedList:"
plotScatter(sortedList)
print sortedList測試
輸入
[544, 757, 514, 875, 371, 44, 538, 296, 155, 148, 612, 847, 352, 973, 654, 135, 956, 197, 655, 270, 280, 609, 175, 891, 450, 128, 75, 260, 248, 540]
輸出
[44, 75, 128, 135, 148, 155, 175, 197, 248, 260, 270, 280, 296, 352, 371, 450, 514, 538, 540, 544, 609, 612, 654, 655, 757, 847, 875, 891, 956, 973]
分析
| 情況 | 性能 |
|---|---|
| Worst case performance: | |
| Best case performance: | |
| Average case performance: | |
| Worst case space complexity: |
參考
