How should I practice Optimal Account Balancing?

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

Is Optimal Account Balancing associated with Salesforce?

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

Problem · Array

Optimal Account Balancing

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● Hard

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Problem statement

You are given an array transactions, where each row [from, to, amount] means that the person with identifier from gave amount units of money to the person with identifier to.

After all listed transactions, people may make additional transfers between any pair of accounts to settle every net balance.

Return the minimum number of additional transfers required so that every person's final net balance is zero.

Function

minTransfers(transactions: int[][]) → int

Examples

Example 1

transactions = [[0,1,10],[2,0,5]]return = 2

Person 0 must receive a net amount of 5, person 1 must receive 10, and person 2 must pay 5. At least two non-zero accounts must receive money, and two transfers are sufficient.

Example 2

transactions = [[0,1,10],[1,0,1],[1,2,5],[2,0,5]]return = 1

The final balances can be settled with one transfer of 4 from person 1 to person 0.

Example 3

transactions = [[0,1,10],[1,2,10],[2,0,10]]return = 0

Every person's incoming and outgoing amounts already cancel, so no additional transfer is needed.

Constraints

1 <= transactions.length <= 8.
transactions[i].length == 3.
0 <= from, to < 12.
from != to.
1 <= amount <= 100.