Added an exercise on recursion.

Added lecture notes for lists and for loop.

1 files changed, 19 insertions, 0 deletions

diff --git a/python/problems/recursion/find_sum/find_sum.py b/python/problems/recursion/find_sum/find_sum.py
new file mode 100644
index 0000000..85f472b
--- /dev/null
+++ b/python/problems/recursion/find_sum/find_sum.py
@@ -0,0 +1,19 @@
+def find_sum(xs, gs):
+    if gs < 0:
+        return False
+    if gs == 0:
+        return True
+    if not xs:
+        return False
+    return find_sum(xs[1:], gs-xs[0]) or find_sum(xs[1:], gs)
+
+print (find_sum([2,7,3,1,4], 10))
+print (find_sum([2,3,2,4], 10))
+print (find_sum([], 10))
+print (find_sum([1,2,3], 2))
+print (find_sum([1,2,3], 7))
+print (find_sum([2,7,3,1,4], 9))
+print (find_sum([2,7,3,2,4], 17))
+
+
+