Count Bulbs Left On after Divisor-Indexed Toggles
Company: LinkedIn
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Other
### Problem
Bulbs 1 through n start off. On round i toggle every bulb whose index is a multiple of i, for rounds 1 through n. Return how many are on at the end.
```cpp
int bulbSwitch(int n);
```
### Examples
```text
n = 10 -> 3
n = 0 -> 0
```
### Constraints
- 0 <= n <= 1000000000.
Overview: Count Bulbs Left On after Divisor-Indexed Toggles. Bulbs 1 through n start off. On round i toggle every bulb whose index is a multiple of i, for rounds 1 through n. Return how many are on at the end.