How should I practice Compute Platform Balance with Optional Destinations?

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

Is Compute Platform Balance with Optional Destinations associated with Stripe?

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

Compute Platform Balance with Optional Destinations

Stripe● EasyINTERNOA

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Problem statement

Process a batch of charges and return the final amount retained by the platform.

Each charge is one comma-separated string with exactly three fields:

amount,destination_account,destination_amount

amount is the positive charge amount. The two destination fields are optional and may be empty.

If both destination fields are empty, the platform retains the full charge amount.
If destination_account is present and destination_amount is empty, the full charge amount is transferred away, so the platform retains zero.
If destination_amount is present, subtract that amount from the charge before adding the remainder to the platform balance. This rule also applies when destination_account is empty.

Return the sum retained by the platform across all charges.

What the interview report shared

The reported OA used optional destination-account and destination-amount parameters in a Platform Balance task. The candidate reasoned about three hidden cases: missing account, account without amount, and amount without account. Those diagnoses were tentative rather than confirmed rules.

Function

calculatePlatformBalance(charges: String[]) → long

Examples

Example 1

charges = ["100,,","80,shop_a,","120,shop_b,50","90,,20"]return = 240

The retained amounts are 100, 0, 70, and 70. Their sum is 240.

Example 2

charges = ["25,merchant_1,5","40,merchant_2,40","10,,0"]return = 30

The platform retains 20, 0, and 10.

Constraints

1 <= charges.length <= 10^5.
1 <= amount <= 10^9.
When present, 0 <= destination_amount <= amount.
A destination account contains lowercase English letters, digits, or underscores.
The final answer fits in a signed 64-bit integer.