From 23484efdad9afc33259adb5753fe2d378e61c37a Mon Sep 17 00:00:00 2001
From: Tapajyoti Bose <44058757+ruppysuppy@users.noreply.github.com>
Date: Wed, 17 Jun 2020 20:39:29 +0530
Subject: [PATCH] Added maximum non-adjacent sum (#2130)

* Added maximum non-adjacent sum

* Bugfix: flake8 test

* Implemented changes (broke tuple unpacking into 2 lines due to flake8 tests)

* Implemented changes v2.0

* Update max_non_adjacent_sum.py

Co-authored-by: Christian Clauss <cclauss@me.com>
---
 dynamic_programming/max_non_adjacent_sum.py | 33 +++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 dynamic_programming/max_non_adjacent_sum.py

diff --git a/dynamic_programming/max_non_adjacent_sum.py b/dynamic_programming/max_non_adjacent_sum.py
new file mode 100644
index 000000000000..1d771f21f3fb
--- /dev/null
+++ b/dynamic_programming/max_non_adjacent_sum.py
@@ -0,0 +1,33 @@
+# Video Explaination: https://www.youtube.com/watch?v=6w60Zi1NtL8&feature=emb_logo
+
+from typing import List
+
+
+def maximum_non_adjacent_sum(nums: List[int]) -> int:
+    '''
+    Find the maximum non-adjacent sum of the integers in the nums input list
+
+    >>> print(maximum_non_adjacent_sum([1, 2, 3]))
+    4
+    >>> maximum_non_adjacent_sum([1, 5, 3, 7, 2, 2, 6])
+    18
+    >>> maximum_non_adjacent_sum([-1, -5, -3, -7, -2, -2, -6])
+    0
+    >>> maximum_non_adjacent_sum([499, 500, -3, -7, -2, -2, -6])
+    500
+    '''
+    if not nums:
+        return 0
+    max_including = nums[0]
+    max_excluding = 0
+    for num in nums[1:]:
+        max_including, max_excluding = (
+            max_excluding + num, max(max_including, max_excluding)
+        )
+    return max(max_excluding, max_including)
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()