Merge pull request larissalages#268 from Vedant-S/patch-5

Added Leetcode 413 Arithmetic Series Solution

Author: larissalages

leetcode/python/Dynamic Programming/413.Arithmetic_Series.py

@@ -0,0 +1,29 @@
+class Solution:
+    def numberOfArithmeticSlices(self, A: List[int]) -> int:
+
+        if len(A) < 3:
+            return 0
+
+        dp = [0 for _ in range(len(A))]
+        d = A[1] - A[0]
+        start = 2
+
+        next_ = self._count(A, d, dp, start)
+        while next_ < len(A):
+            d = A[next_] - A[next_ - 1]
+            start = next_ + 1
+            next_ = self._count(A, d, dp, start)
+
+        return sum(dp)
+
+def _count(self, A, d, dp, start):
+
+        for i in range(start, len(A)):
+            if A[i] - A[i - 1] == d:
+                dp[i] = dp[i - 1] + 1
+            else:
+                return i
+
+        return len(A)
+
+