How should I practice Defer Expenses to Preserve Balance?

Start by reading the full statement, solve the visible examples, then compare the pattern against related DRW phone screen problems in FastPrep.

Is Defer Expenses to Preserve Balance associated with DRW?

FastPrep tags this as a DRW phone screen coding practice problem when the problem catalog has that company and stage context.

Defer Expenses to Preserve Balance

DRW● MediumINTERNPHONE SCREEN

Learn

Problem statement

You are given a chronological array transactions. Positive values are income and negative values are expenses. The running balance must never become negative.

You may defer an expense by removing it from its current position and appending it after every non-deferred transaction. Deferred expenses retain their relative order. Return the minimum number of expenses that must be deferred.

Function

minimumDeferredExpenses(transactions: int[]) → int

Examples

Example 1

transactions = [4,-5,3,-2,1]return = 1

Defer -5; the order [4,3,-2,1,-5] never has a negative prefix.

Example 2

transactions = [10,-4,-8,7,-6,5]return = 1

Deferring -8 is sufficient.

Example 3

transactions = [3,-1,-2,4]return = 0

Every original prefix already has a nonnegative balance.

Constraints

1 <= transactions.length <= 100000
-1000000000 <= transactions[i] <= 1000000000
The total sum of transactions is nonnegative.