added radix sort in python (tornado-12#102)

* added bucket sort in c++

* added counting sort in c++

* added radix sort in python

Co-authored-by: satks <[email protected]>

Python/RadixSort.py

@@ -0,0 +1,58 @@
+# 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])