Problems › TypeScript › scheduling
Extra pay for overnight hours
Hours between 22:00 and 06:00 carry a premium: each premium hour earns premiumPerHour on top of the base. Compute the added pay for one shift.
- The premium band is [22:00, 24:00) plus [00:00, 06:00), on the minute.
- A shift is described by start and finish minutes past midnight; a finish earlier than start means the shift crosses midnight.
- Return only the added pay: premium minutes ÷ 60 × premiumPerHour, rounded down.
nightPremium(start: int, finish: int, premiumPerHour: int) → int
Where you start
function nightPremium(start: number, finish: number, premiumPerHour: number): number {
}Worked examples
| Call | Result |
|---|---|
nightPremium(1320, 1380, 3000) | 3000 |
nightPremium(360, 420, 1000) | 0 |
nightPremium(1260, 1440, 1000) | 2000 |
nightPremium(0, 120, 1000) | 2000 |
Hint
Split the shift against the two half-open bands; a crossing shift spans [start, 1440) plus [0, finish).
Reference solution in TypeScript
function nightPremium(start: number, finish: number, premiumPerHour: number): number {
if (start === finish) return 0;
const overlap = (a: number, b: number, lo: number, hi: number) => Math.max(0, Math.min(b, hi) - Math.max(a, lo));
let minutes: number;
if (start < finish) {
minutes = overlap(start, finish, 0, 360) + overlap(start, finish, 1320, 1440);
} else {
minutes = overlap(start, 1440, 1320, 1440) + overlap(0, finish, 0, 360);
}
return Math.floor((minutes * premiumPerHour) / 60);
}