Package g0301_0400.s0319_bulb_switcher

Class Solution

java.lang.Object

g0301_0400.s0319_bulb_switcher.Solution

public class Solution
extends Object

319 - Bulb Switcher.<p>Medium</p> <p>There are <code>n</code> bulbs that are initially off. You first turn on all the bulbs, then you turn off every second bulb.</p> <p>On the third round, you toggle every third bulb (turning on if it&rsquo;s off or turning off if it&rsquo;s on). For the <code>i^th</code> round, you toggle every <code>i</code> bulb. For the <code>n^th</code> round, you only toggle the last bulb.</p> <p>Return <em>the number of bulbs that are on after <code>n</code> rounds</em>.</p> <p><strong>Example 1:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2020/11/05/bulb.jpg" alt="" /></p> <p><strong>Input:</strong> n = 3</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> At first, the three bulbs are [off, off, off]. After the first round, the three bulbs are [on, on, on]. After the second round, the three bulbs are [on, off, on]. After the third round, the three bulbs are [on, off, off]. So you should return 1 because there is only one bulb is on.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> n = 0</p> <p><strong>Output:</strong> 0</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> n = 1</p> <p><strong>Output:</strong> 1</p> <p><strong>Constraints:</strong></p> <ul> <li><code>0 <= n <= 10⁹</code></li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	bulbSwitch(int n)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

bulbSwitch

public int bulbSwitch(int n)