robinhood-ledger

Repair this code

Add up a ledger where an entry that has already been posted must not be posted again.

today's brief

2020. Robinhood customers open the app and find a cash balance that has wandered somewhere strange, sometimes deeply negative, because the ledger behind the display posted the same option assignment more than once. Support told people to ignore the number while the books were rebuilt. Reposted entries are still sitting in this ledger. Post each one once.

See it in action

balance({1,2,2,3}, {100,-30,-30,5}, 4)

Expected result

Your checklist

For your own tracking. Tests grade your code.

ids and amounts hold n ledger entries in order: entry i carries the id ids[i] and moves amounts[i], which can be negative.
An entry whose id has already appeared earlier in the ledger is a repost and moves nothing.
Return the balance after the whole ledger, starting from zero.

More examples

balance({1,2,3}, {10,20,30}, 3)

Expected result

balance({7,7,7}, {-500,-500,-500}, 3)

Expected result

-500

Constraints

Expected files

ledger.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions

robinhood-ledger

Repair this code

Add up a ledger where an entry that has already been posted must not be posted again.

today's brief

See it in action

balance({1,2,2,3}, {100,-30,-30,5}, 4)

Expected result

Your checklist

For your own tracking. Tests grade your code.

ids and amounts hold n ledger entries in order: entry i carries the id ids[i] and moves amounts[i], which can be negative.
An entry whose id has already appeared earlier in the ledger is a repost and moves nothing.
Return the balance after the whole ledger, starting from zero.

More examples

balance({1,2,3}, {10,20,30}, 3)

Expected result

balance({7,7,7}, {-500,-500,-500}, 3)

Expected result

-500

Constraints

Expected files

ledger.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions