add boilerplate for second edition

first_edition/ebook_src/dynamic_programming/memo.py

@@ -0,0 +1,42 @@
+#!/usr/bin/python3
+
+__author__ = "bt3"
+
+
+from functools import wraps
+from do_benchmark import benchmark
+
+def memo(func):
+    ''' an example of dynamic programming using a memoizing decorator '''
+    cache = {}
+    @wraps(func)
+    def wrap(*args):
+        if args not in cache:
+            cache[args] = func(*args)
+        return cache[args]
+    return wrap
+
+@memo
+def find_fibonacci_seq_rec(n):
+    ''' implements the nth fibonacci value in a recursive exponential runtime '''
+    if n < 2: return n
+    return find_fibonacci_seq_rec(n - 1) + find_fibonacci_seq_rec(n - 2)
+
+def test_memo():
+    n = 50
+    # find_fibonacci_seq_rec = memo(find_fibonacci_seq_rec)
+    # @benchmark
+    print(find_fibonacci_seq_rec(n))
+
+
+if __name__ == '__main__':
+    test_memo()
+
+
+
+
+
+
+
+
+