基数排序的Python程序
基数排序算法
1)对每个数字 i 执行以下操作,其中 i 从最低有效位到最高有效位变化。
- 根据第 i 位使用计数排序(或任何稳定排序)对输入数组进行排序。
Python3
# Python program for implementation of Radix Sort
# A function to do counting sort of arr[] according to
# the digit represented by exp.
def countingSort(arr, exp1):
n = len(arr)
# The output array elements that will have sorted arr
output = [0] * (n)
# initialize count array as 0
count = [0] * (10)
# Store count of occurrences in count[]
for i in range(0, n):
index = (arr[i]/exp1)
count[int((index)%10)] += 1
# Change count[i] so that count[i] now contains actual
# position of this digit in output array
for i in range(1,10):
count[i] += count[i-1]
# Build the output array
i = n-1
while i>=0:
index = (arr[i]/exp1)
output[ count[ int((index)%10) ] - 1] = arr[i]
count[int((index)%10)] -= 1
i -= 1
# Copying the output array to arr[],
# so that arr now contains sorted numbers
i = 0
for i in range(0,len(arr)):
arr[i] = output[i]
# Method to do Radix Sort
def radixSort(arr):
# Find the maximum number to know number of digits
max1 = max(arr)
# Do counting sort for every digit. Note that instead
# of passing digit number, exp is passed. exp is 10^i
# where i is current digit number
exp = 1
while max1/exp > 0:
countingSort(arr,exp)
exp *= 10
# Driver code to test above
arr = [ 170, 45, 75, 90, 802, 24, 2, 66]
radixSort(arr)
for i in range(len(arr)):
print(arr[i],end=" ")
# This code is contributed by Mohit Kumra
# This code is updated by Sudeep Saxena(saxenasudeepcse@gmail.com) on July 9, 2020
输出:
2 24 45 66 75 90 170 802
有关更多详细信息,请参阅有关 Radix Sort 的完整文章!