Java Bit Count bitCount(int x)

Description

bit Count

License

Apache License

Declaration

public static int bitCount(int x) 

Method Source Code

//package com.java2s;
/*/*from w w w  .j  av a  2  s.  c  o  m*/
 * Copyright 2008 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

public class Main {
    public static int bitCount(int x) {
        // Courtesy the University of Kentucky
        // http://aggregate.org/MAGIC/#Population%20Count%20(Ones%20Count)
        x -= ((x >> 1) & 0x55555555);
        x = (((x >> 2) & 0x33333333) + (x & 0x33333333));
        x = (((x >> 4) + x) & 0x0f0f0f0f);
        x += (x >> 8);
        x += (x >> 16);
        return x & 0x0000003f;
    }
}

Related

1. bitCount(byte b)
2. bitCount(final Integer i)
3. bitCount(int i)
4. bitcount(int num)
5. bitCount(String s)
6. bitCountSlow(int x)
7. bitLength(byte[] bytes)
8. bitLength(final int byteLength)