Problems › TypeScript › warmup
Factorial
Return n! — the product of every integer from 1 to n.
- 0! is 1.
- n stays within 0..12, so the result always fits in a 32-bit int.
factorial(n: int) → int
Where you start
function factorial(n: number): number {
}Worked examples
| Call | Result |
|---|---|
factorial(0) | 1 |
factorial(1) | 1 |
factorial(5) | 120 |
factorial(10) | 3628800 |
Hint
Start an accumulator at 1 and multiply up to n. A loop is plenty.
Reference solution in TypeScript
function factorial(n: number): number {
let acc = 1;
for (let i = 2; i <= n; i++) acc *= i;
return acc;
}