add counting sort algorithm

Author: lowjack1

counting_sort.py

@@ -0,0 +1,34 @@
+"""
+    COUNTING SORT ALGORITHM
+
+        Assumption :
+        1. Element of array should be integer
+        2. Each integer should be in the range of [0, 10000000]
+
+        Time Complexity : O(max_value)
+        Space Complexity : O(max_value)
+"""
+
+def countingSort(unsorted_arr):
+    """ Sort natural number by counting sort algorithm """
+    max_value = max(unsorted_arr)
+    # Create a count array kind of like the hash map of size max_value
+    count = [0 for _ in range(max_value + 1)]
+    for x in unsorted_arr:
+        # Get the count of each element of the unsorted array
+        count[x] += 1
+
+    # Store element in non-decreasing order
+    sorted_arr = []
+    for x in range(max_value+1):
+        # Since we are iterating in ascending order, hence it is known for sure that 
+        # anay element which is going to append to the "sorted_arr" will be in sorted array
+        for y in range(count[x]):
+            sorted_arr.append(x)
+
+    return sorted_arr
+
+# Get a list of integer from the user
+unsorted_arr = list(map(int, input().strip().split()))
+# Print sorted list of integer
+print(*countingSort(unsorted_arr))