How should I practice Account Balance Manager Part 1 - Calculate Totals?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Stripe onsite interview problems in FastPrep.

Is Account Balance Manager Part 1 - Calculate Totals associated with Stripe?

FastPrep tags this as a Stripe onsite interview coding practice problem when the problem catalog has that company and stage context.

Problem · Hash Table

Account Balance Manager Part 1 - Calculate Totals

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Problem statement

Source note: July 26, 2026 — 🌺 I re-audited the original author-written sources and rebuilt this practice version from the available interview reports. It is about a 25% match to the available source. The Stripe coding-round context, Account Balance / Bank Transaction topic, and three-question progression come directly from the sources. A supporting report also confirms that the final follow-up passes a platform account whose funds may cover negative accounts. The individual Part 1 objective, balance-update rules, original function signature, runnable input format, constraints, examples, and edge-case behavior were not shown, so FastPrep supplied them as a bounded practice contract rather than presenting them as source facts. If a more complete author-written source becomes available, I will continue refining this problem step by step.

Practice sequence

Part 1: Calculate Totals (you are here)
Part 2: Reject Overdrafts
Part 3: Platform Coverage

What the interview report shared

The coding round centered on Account Balance / Bank Transaction and contained three questions.

Practice contract

For this exercise, assume transactions arrive in order as account_id,amount strings. A positive amount is a deposit and a negative amount is a withdrawal.

Process every transaction and calculate each account's final balance. Return only accounts with a strictly positive final balance. Format each result as account_id:balance and sort the results lexicographically by account identifier.

Function

getAccountBalances(transactions: String[]) → String[]

Examples

Example 1

transactions = ["account_A,100", "account_B,50", "account_A,-30", "account_C,200", "account_B,-50"]return = ["account_A:70", "account_C:200"]

account_A: 100 - 30 = 70 (positive, kept). account_B: 50 - 50 = 0 (zero, removed). account_C: 200 (positive, kept). Output sorted by account_id.

Example 2

transactions = []return = []

An empty transaction list yields no accounts.

Constraints

Each transaction is "account_id,amount"; amount is an integer (positive deposit, negative withdrawal).
Process transactions in the given order, summing per account.
Return only accounts with a final balance strictly greater than 0.
Output entries are "account_id:balance" sorted alphabetically by account_id.