Package g0101_0200.s0191_number_of_1_bits

Class Solution

java.lang.Object

g0101_0200.s0191_number_of_1_bits.Solution

public class Solution
extends Object

191 - Number of 1 Bits.<p>Easy</p> <p>Write a function that takes an unsigned integer and returns the number of &lsquo;1&rsquo; bits it has (also known as the <a href="http://en.wikipedia.org/wiki/Hamming_weight" target="_top">Hamming weight</a>).</p> <p><strong>Note:</strong></p> <ul> <li>Note that in some languages, such as Java, there is no unsigned integer type. In this case, the input will be given as a signed integer type. It should not affect your implementation, as the integer&rsquo;s internal binary representation is the same, whether it is signed or unsigned.</li> <li>In Java, the compiler represents the signed integers using <a href="https://en.wikipedia.org/wiki/Two%27s_complement" target="_top">2&rsquo;s complement notation</a>. Therefore, in <strong>Example 3</strong> , the input represents the signed integer. <code>-3</code>.</li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> n = 00000000000000000000000000001011</p> <p><strong>Output:</strong> 3</p> <p><strong>Explanation:</strong> The input binary string <strong>00000000000000000000000000001011</strong> has a total of three &lsquo;1&rsquo; bits.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> n = 00000000000000000000000010000000</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> The input binary string <strong>00000000000000000000000010000000</strong> has a total of one &lsquo;1&rsquo; bit.</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> n = 11111111111111111111111111111101</p> <p><strong>Output:</strong> 31</p> <p><strong>Explanation:</strong> The input binary string <strong>11111111111111111111111111111101</strong> has a total of thirty one &lsquo;1&rsquo; bits.</p> <p><strong>Constraints:</strong></p> <ul> <li>The input must be a <strong>binary string</strong> of length <code>32</code>.</li> </ul> <p><strong>Follow up:</strong> If this function is called many times, how would you optimize it?</p>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	hammingWeight(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

hammingWeight

public int hammingWeight(int n)