Subarrays with Sum in a Band — Solution & Editorial
'Sum in [LO, HI]' = (subarrays with sum ≤ HI) − (sum ≤ LO−1); each is a sliding window counting valid left endpoints per right endpoint (positivity makes the window monotone).
Complexity: O(N)
'Sum in [LO, HI]' = (subarrays with sum ≤ HI) − (sum ≤ LO−1); each is a sliding window counting valid left endpoints per right endpoint (positivity makes the window monotone).
Complexity: O(N)