radix__sort.py

Author: abhishekfrayne

sorts/radix__sort.py

@@ -0,0 +1,57 @@
+# Python program for implementation of Radix Sort 
+
+# A function to do counting sort of arr[] according to 
+# the digit represented by exp. 
+def counting_sort(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 radix_sort(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:
+		counting_sort(arr,exp)
+		exp *= 10
+
+# Driver code to test above
+arr = [ 170, 45, 75, 90, 802, 24, 2, 66]
+radix_sort(arr)
+
+for i in range(len(arr)):
+	print(arr[i],end=" ")