Add sleep-sort (#1867)

* added sleepsort

Adding sleepsort

* Add doctest and typing for sleepsort

* Use self-descriptive variable name

* Update sleepsort.py

* Update sorts/sleepsort.py

Co-authored-by: John Law <johnlaw.po@gmail.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

sorts/sleepsort.py

@@ -0,0 +1,48 @@
+"""Sleepsort is probably the wierdest of all sorting functions
+with time-complexity of O(max(input)+n) which is
+quite different from almost all other sorting techniques.
+If the number of inputs is small then the complexity
+can be approximated to be O(max(input)) which is a constant
+
+If the number of inputs is large, the complexity is
+approximately O(n).
+
+This function uses multithreading a kind of higher order programming
+and calls n functions, each with a sleep time equal to its number.
+Hence each of the functions wake in sorted form.
+
+This function is not stable for very large values.
+
+https://rosettacode.org/wiki/Sorting_algorithms/Sleep_sort
+"""
+
+from time import sleep
+from threading import Timer
+from typing import List
+
+
+def sleepsort(values: List[int]) -> List[int]:
+    """
+    Sort the list using sleepsort.
+    >>> sleepsort([3, 2, 4, 7, 3, 6, 9, 1])
+    [1, 2, 3, 3, 4, 6, 7, 9]
+    >>> sleepsort([3, 2, 1, 9, 8, 4, 2])
+    [1, 2, 2, 3, 4, 8, 9]
+    """
+    sleepsort.result = []
+    def append_to_result(x):
+        sleepsort.result.append(x)
+    mx = values[0]
+    for v in values:
+        if mx < v:
+            mx = v
+        Timer(v, append_to_result, [v]).start()
+    sleep(mx+1)
+    return sleepsort.result
+ 
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+    x = [3, 2, 4, 7, 3, 6, 9, 1]
+    sorted_x = sleepsort(x)
+    print(sorted_x)