https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum

medium/number_of_sub_arrays_with_odd_sum.py

@@ -0,0 +1,22 @@
+# https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum
+
+from typing import List
+
+MOD = 10 ** 9 + 7
+class Solution:
+    def numOfSubarrays(self, arr: List[int]) -> int:
+        odd_count = int(arr[0] % 2 == 1)
+        for i in range(1, len(arr)):
+            arr[i] += arr[i -1]
+            odd_count += int(arr[i] % 2 == 1)
+
+        result = odd_count
+        curr = 0
+        for i in range(len(arr)):
+            if (arr[i] - curr) % 2 == 1:
+                odd_count -= 1
+                odd_count = len(arr) - i - 1 - odd_count
+            result += odd_count
+            curr = arr[i]
+        return result % MOD
+