How should I practice Passing Cars?

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

Is Passing Cars associated with Bloomberg LP?

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

Passing Cars

Bloomberg LP● EasyNEW GRADPHONE SCREEN

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Problem statement

Each value in directions describes a car's travel direction along a two-way road: 1 travels east and 0 travels west. Return the number of pairs (i,j) with i < j, directions[i] == 1, and directions[j] == 0.

Function

countPassingCars(directions: int[]) → long

Examples

Example 1

directions = [1,0,1,0,0,1]return = 5

The first eastbound car passes three westbound cars and the second passes two.

Constraints

0 <= directions.length <= 2 * 10^5.
Every value is 0 or 1.