Create 0930-binary-subarrays-with-sum.py

Author: a93a

python/0930-binary-subarrays-with-sum.py

@@ -0,0 +1,17 @@
+class Solution:
+    def numSubarraysWithSum(self, nums: List[int], goal: int) -> int:
+
+        def helper(x):
+            if x < 0: return 0
+
+            res = 0
+            l, cur = 0, 0
+            for r in range(len(nums)):
+                cur += nums[r]
+                while cur > x:
+                    cur -= nums[l]
+                    l += 1
+                res += (r - l + 1)
+            return res
+        
+        return helper(goal) - helper(goal - 1)