nyse-gateways

Your mission

Count the configuration ids that are live on the first set of gateways and absent from the second.

today's brief

July 8, 2015. The New York Stock Exchange halts trading at 11:32 in the morning and stays dark until after three. A configuration change had gone out to some of its gateways the night before and not to the others, so machines running two different rulebooks tried to talk to each other. That same day United grounded its whole fleet and the Wall Street Journal website fell over. Nobody believed the coincidence.

See it in action

missing_from_backup({10,20,30,40}, 4, {10,30}, 2)

Expected result

Your checklist

For your own tracking. Tests grade your code.

live holds n ids in increasing order, backup holds m ids in increasing order.
Neither list repeats an id.
Return how many of the live ids do not appear in backup.
Return 0 when live is empty.

More examples

missing_from_backup({10,20,30,40}, 4, {10,20,30,40}, 4)

Expected result

missing_from_backup({1,2,3}, 3, {4,5,6}, 3)

Expected result

Constraints

Expected files

gateway.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions

nyse-gateways

Your mission

Count the configuration ids that are live on the first set of gateways and absent from the second.

today's brief

See it in action

missing_from_backup({10,20,30,40}, 4, {10,30}, 2)

Expected result

Your checklist

For your own tracking. Tests grade your code.

live holds n ids in increasing order, backup holds m ids in increasing order.
Neither list repeats an id.
Return how many of the live ids do not appear in backup.
Return 0 when live is empty.

More examples

missing_from_backup({10,20,30,40}, 4, {10,20,30,40}, 4)

Expected result

missing_from_backup({1,2,3}, 3, {4,5,6}, 3)

Expected result

Constraints

Expected files

gateway.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions