Create tallest-billboard.py

Author: kamyu104

Python/tallest-billboard.py

@@ -0,0 +1,23 @@
+# Time:  O(n * 3^(n/2))
+# Space: O(3^(n/2))
+
+import collections
+
+
+class Solution(object):
+    def tallestBillboard(self, rods):
+        """
+        :type rods: List[int]
+        :rtype: int
+        """
+        def dp(A):
+            lookup = collections.defaultdict(int)
+            lookup[0] = 0
+            for x in A:
+                for d, y in lookup.items():
+                    lookup[d+x] = max(lookup[d+x], y)
+                    lookup[abs(d-x)] = max(lookup[abs(d-x)], y + min(d, x))
+            return lookup
+
+        left, right = dp(rods[:len(rods)//2]), dp(rods[len(rods)//2:])
+        return max(left[d]+right[d]+d for d in left if d in right)