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  2. 2 Additional Online Test (If Required)
  3. 3 Office Interview with Hiring Manager
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  5. 5 Paid Test Task and Follow-Up Interview
  6. 6 Iterative Paid Test Tasks
  7. 7 Office Verification
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Problems > Zero-Sum Subarrays > Editorial

Zero-Sum Subarrays — Solution & Editorial

Back to the Problem

A subarray (l, r] sums to zero iff prefix[r] = prefix[l]. Count equal prefix values with a hash map, adding C(k, 2) pairs incrementally.

Complexity: O(N)

Watch out: Remember the empty prefix (value 0) — it pairs with every later prefix summing to 0.