python selectionSort 实现错误

Author: corningsun

.gitignore

@@ -13,4 +13,5 @@ _book
 # eBook build output
 *.epub
 *.mobi
-*.pdf
+*.pdf
+\.idea/

2.selectionSort.md

@@ -42,10 +42,15 @@ function selectionSort(arr) {
 
 ```python
 def selectionSort(arr):
- for i in range(len(arr)-1):
- for j in range(i+1, len(arr)):
- if arr[j] < arr[i]:
- arr[i], arr[j] = arr[j], arr[i]
+ for i in range(len(arr) - 1):
+ # 记录最小数的索引
+ minIndex = i
+ for j in range(i + 1, len(arr)):
+ if arr[j] < arr[minIndex]:
+ minIndex = j
+ # i 不是最小数时，将 i 和最小数进行交换
+ if i != minIndex:
+ arr[i], arr[minIndex] = arr[minIndex], arr[i]
  return arr
 ```
 

src/pythonSortTest.py

@@ -2,77 +2,89 @@
 # Create by LokiSharp(loki.sharp#gmail) at 2017-1-22
 '''
 
-TOTAL=5000
+TOTAL = 5000
+
 
 def sortTest(func, total=1000):
  import random, copy, operator, math, time
- arrList = [i for i in range(-math.floor(total/2),math.ceil(total/2))]
+ arrList = [i for i in range(-math.floor(total / 2), math.ceil(total / 2))]
  arrListR = copy.deepcopy(arrList)
- while operator.eq(arrList,arrListR):
+ while operator.eq(arrList, arrListR):
  random.shuffle(arrListR)
- #print("--- [Origin List]", arrList, "Use", func.__name__,"with Total:", len(arrList))
- #print("--> [Random List]", arrListR, "Use", func.__name__,"with Total:", len(arrList))
+ # print("--- [Origin List]", arrList, "Use", func.__name__,"with Total:", len(arrList))
+ # print("--> [Random List]", arrListR, "Use", func.__name__,"with Total:", len(arrList))
  start = time.clock()
  arrListR = func(arrListR)
  end = time.clock()
- runtime = end-start
- #print("--> [Sorted List]", arrListR, "Use", func.__name__,"with Total:", len(arrList))
+ runtime = end - start
+ # print("--> [Sorted List]", arrListR, "Use", func.__name__,"with Total:", len(arrList))
  if operator.eq(arrList, arrListR):
- print("[Success]", func.__name__,"with Total:", len(arrList),"in %.5fs" % runtime)
+ print("[Success]", func.__name__, "with Total:", len(arrList), "in %.5fs" % runtime)
  return True
  else:
- print("[Fail]", func.__name__,"with Total:", len(arrList),"in %.5fs" % runtime)
+ print("[Fail]", func.__name__, "with Total:", len(arrList), "in %.5fs" % runtime)
  return False
 
+
 def bubbleSort(arr):
  for i in range(1, len(arr)):
- for j in range(0, len(arr)-i):
- if arr[j] > arr[j+1]:
+ for j in range(0, len(arr) - i):
+ if arr[j] > arr[j + 1]:
  arr[j], arr[j + 1] = arr[j + 1], arr[j]
  return arr
 
+
 def selectionSort(arr):
- for i in range(len(arr)-1):
- for j in range(i+1, len(arr)):
- if arr[j] < arr[i]:
- arr[i], arr[j] = arr[j], arr[i]
+ for i in range(len(arr) - 1):
+ # 记录最小数的索引
+ minIndex = i
+ for j in range(i + 1, len(arr)):
+ if arr[j] < arr[minIndex]:
+ minIndex = j
+ # i 不是最小数时，将 i 和最小数进行交换
+ if i != minIndex:
+ arr[i], arr[minIndex] = arr[minIndex], arr[i]
  return arr
 
+
 def insertionSort(arr):
  for i in range(len(arr)):
- preIndex = i-1
+ preIndex = i - 1
  current = arr[i]
  while preIndex >= 0 and arr[preIndex] > current:
- arr[preIndex+1] = arr[preIndex]
- preIndex-=1
- arr[preIndex+1] = current
+ arr[preIndex + 1] = arr[preIndex]
+ preIndex -= 1
+ arr[preIndex + 1] = current
  return arr
 
+
 def shellSort(arr):
  import math
- gap=1
- while(gap < len(arr)/3):
- gap = gap*3+1
+ gap = 1
+ while (gap < len(arr) / 3):
+ gap = gap * 3 + 1
  while gap > 0:
- for i in range(gap,len(arr)):
+ for i in range(gap, len(arr)):
  temp = arr[i]
- j = i-gap
- while j >=0 and arr[j] > temp:
- arr[j+gap]=arr[j]
- j-=gap
- arr[j+gap] = temp
- gap = math.floor(gap/3)
+ j = i - gap
+ while j >= 0 and arr[j] > temp:
+ arr[j + gap] = arr[j]
+ j -= gap
+ arr[j + gap] = temp
+ gap = math.floor(gap / 3)
  return arr
 
+
 def mergeSort(arr):
  import math
- if(len(arr)<2):
+ if (len(arr) < 2):
  return arr
- middle = math.floor(len(arr)/2)
+ middle = math.floor(len(arr) / 2)
  left, right = arr[0:middle], arr[middle:]
  return merge(mergeSort(left), mergeSort(right))
 
-def merge(left,right):
+
+def merge(left, right):
  result = []
  while left and right:
  if left[0] <= right[0]:
@@ -85,38 +97,43 @@ def merge(left,right):
  result.append(right.pop(0));
  return result
 
+
 def quickSort(arr, left=None, right=None):
- left = 0 if not isinstance(left,(int, float)) else left
- right = len(arr)-1 if not isinstance(right,(int, float)) else right
+ left = 0 if not isinstance(left, (int, float)) else left
+ right = len(arr) - 1 if not isinstance(right, (int, float)) else right
  if left < right:
  partitionIndex = partition(arr, left, right)
- quickSort(arr, left, partitionIndex-1)
- quickSort(arr, partitionIndex+1, right)
+ quickSort(arr, left, partitionIndex - 1)
+ quickSort(arr, partitionIndex + 1, right)
  return arr
 
+
 def partition(arr, left, right):
  pivot = left
- index = pivot+1
+ index = pivot + 1
  i = index
- while  i <= right:
+ while i <= right:
  if arr[i] < arr[pivot]:
  swap(arr, i, index)
- index+=1
- i+=1
- swap(arr,pivot,index-1)
- return index-1
+ index += 1
+ i += 1
+ swap(arr, pivot, index - 1)
+ return index - 1
+
 
 def swap(arr, i, j):
  arr[i], arr[j] = arr[j], arr[i]
 
+
 def buildMaxHeap(arr):
  import math
- for i in range(math.floor(len(arr)/2),-1,-1):
- heapify(arr,i)
+ for i in range(math.floor(len(arr) / 2), -1, -1):
+ heapify(arr, i)
+
 
 def heapify(arr, i):
- left = 2*i+1
- right = 2*i+2
+ left = 2 * i + 1
+ right = 2 * i + 2
  largest = i
  if left < arrLen and arr[left] > arr[largest]:
  largest = left
@@ -127,39 +144,44 @@ def heapify(arr, i):
  swap(arr, i, largest)
  heapify(arr, largest)
 
+
 def swap(arr, i, j):
  arr[i], arr[j] = arr[j], arr[i]
 
+
 def heapSort(arr):
  global arrLen
  arrLen = len(arr)
  buildMaxHeap(arr)
- for i in range(len(arr)-1,0,-1):
- swap(arr,0,i)
- arrLen -=1
+ for i in range(len(arr) - 1, 0, -1):
+ swap(arr, 0, i)
+ arrLen -= 1
  heapify(arr, 0)
  return arr
 
+
 def countingSort(arr, maxValue=None):
- bucketLen = maxValue+1
- bucket = [0]*bucketLen
- sortedIndex =0
+ bucketLen = maxValue + 1
+ bucket = [0] * bucketLen
+ sortedIndex = 0
  arrLen = len(arr)
  for i in range(arrLen):
  if not bucket[arr[i]]:
- bucket[arr[i]]=0
- bucket[arr[i]]+=1
+ bucket[arr[i]] = 0
+ bucket[arr[i]] += 1
  for j in range(bucketLen):
- while bucket[j]>0:
+ while bucket[j] > 0:
  arr[sortedIndex] = j
- sortedIndex+=1
- bucket[j]-=1
+ sortedIndex += 1
+ bucket[j] -= 1
  return arr
 
-sortTest(bubbleSort, TOTAL)
-sortTest(selectionSort, TOTAL)
-sortTest(insertionSort, TOTAL)
-sortTest(shellSort, TOTAL)
-sortTest(mergeSort, TOTAL)
-sortTest(quickSort, TOTAL)
-sortTest(heapSort, TOTAL)
+
+if __name__ == '__main__':
+ sortTest(bubbleSort, TOTAL)
+ sortTest(selectionSort, TOTAL)
+ sortTest(insertionSort, TOTAL)
+ sortTest(shellSort, TOTAL)
+ sortTest(mergeSort, TOTAL)
+ sortTest(quickSort, TOTAL)
+ sortTest(heapSort, TOTAL)