move pigeon hole to sort folder

Author: prashanth9962

Arrays-Sorting/src/Pigeon_hole/pigeon_hole.py

@@ -0,0 +1,28 @@
+
+
+"""Pigeonhole sorting is a sorting algorithm that is suitable for sorting lists of elements
+where the number of elements (n) and the length of the range of possible key values (N) are approximately the same"""
+
+# Time complexity O(n + N)
+# Space complexity O(n)
+
+def pigeonhole_sort(list):
+    min_elem = min(list)
+    max_elem = max(list)
+    size = max_elem - min_elem + 1
+    holes = [0] * size               # auxiliary list of pigeonholes
+    for x in list:                   # Populate the pigeonholes.
+        holes[x - min_elem] += 1
+    i = 0
+    for count in range(size):         # Put the elements back into the array in order.
+        while holes[count] > 0:
+            holes[count] -= 1
+            list[i] = count + min_elem
+            i += 1
+    return list
+
+
+list = [10,2,7,9,4,5,3]
+print pigeonhole_sort(list)
+
+