Merge pull request larymak#247 from tamilselvi53/dsa

Added Radix sort

Author: larymak

Data Structures and Algorithms/README.md

@@ -39,3 +39,8 @@
 - Selection Sort
 
 - Binary Tree traversal
+
+- Radix Sort (for numbers) using Counting Sort
+1. Find the largest number int given array. It has n digits. Therefore, the loop should go up to hundreds place (n times)
+2. It is stable sorting algorithm
+3. Sort the elements based on the unit place digits, then tenth place digits ... nTh place digits

Data Structures and Algorithms/radix_sort.py

@@ -0,0 +1,40 @@
+def countingSort(array, place):
+    size = len(array)
+    output = [0] * size
+    count = [0] * 10
+
+    # Calculate count of elements
+    for i in range(0, size):
+        index = array[i] // place
+        count[index % 10] += 1
+
+    # Calculate cumulative count
+    for i in range(1, 10):
+        count[i] += count[i - 1]
+
+    # Place the elements in sorted order
+    i = size - 1
+    while i >= 0:
+        index = array[i] // place
+        output[count[index % 10] - 1] = array[i]
+        count[index % 10] -= 1
+        i -= 1
+
+    for i in range(0, size):
+        array[i] = output[i]
+
+
+# Main function to implement radix sort
+def radixSort(array):
+    # Get maximum element
+    max_element = max(array)
+
+    place = 1
+    while max_element // place > 0:
+        countingSort(array, place)
+        place *= 10
+
+
+data = [121, 432, 564, 23, 1, 45, 788]
+radixSort(data)
+print(data)