Bulb Switcher
Medium
Topics
There are n bulbs initially off. On round i you toggle every i-th bulb (round 1 toggles all). After n rounds, return how many bulbs are on. A bulb ends on iff it has an odd number of divisors, i.e. it is a perfect square.
Example 1
Input: n = 3 Output: 1
Example 2
Input: n = 0 Output: 0
Example 3
Input: n = 99 Output: 9
Constraints
- 0 <= n <= 10^6
Run ⌘' · Submit ⌘⏎
SensAI