Count Multiples of 3 in Range — Solution & Editorial | Jobs at Avian IT

Hiring process8 levels

1 IQ Test
2 Additional Online Test (If Required)
3 Office Interview with Hiring Manager
4 Unpaid Test Task (Motivation Check)
5 Paid Test Task and Follow-Up Interview
6 Iterative Paid Test Tasks
7 Office Verification
8 Final Interview with the Founder

Problems > Count Multiples of 3 in Range > Editorial

Count Multiples of 3 in Range — Solution & Editorial

Back to the Problem

Precompute prefix counts of the predicate; each query is pre[r] − pre[l−1] in O(1).

Complexity: O(N + Q)