Bitwise operator

Bitwise operator

Count Bit Set
package com.algo.bits;
import java.io.*; 
 
class countSetBits
{
    /* Function to get no of set 
    bits in binary representation 
    of positive integer n */
    static int countSetBits(int n)
    {
        int count = 0;
        while (n > 0)
        {
            count += n & 1;
            n >>= 1;
        }
        return count;
    }
    
    static int countSetBits(long n)
    {
        int count = 0;
        while (n > 0)
        {
            count += n & 1;
            n >>= 1;
        }
        return count;
    }
 
    // driver program
    public static void main(String args[])
    {
        long i = 1000000099;
        System.out.println(countSetBits(i));
    }
}
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Find Duplicate in Array :
package com.algo.bits;

import java.util.ArrayList;
import java.util.List;

public class FindDuplicateInArray {

	public static List<Integer> findDup(int[] arr) {
		short status = 0;
		List<Integer> l = new ArrayList<Integer>();
		byte digit;

		for (int temp = 0; temp < arr.length; temp++) {
			digit = (byte) arr[temp];

			if ((status & (1 << (digit))) > 0) {
				l.add(arr[temp]);
				// return false;
			} else
				status |= 1 << (digit);

		}
		return l;
	}

	static int countSetBits(int n) {
		int count = 0;
		while (n > 0) {
			count += n & 1;
			n >>= 1;
		}
		return count;
	}

	public void findNumber(int no) {

	}

	// Driver code
	public static void main(String[] args) throws java.lang.Exception {
		int[] arr = { 1, 5, 1, 10, 12, 10 };
		for (int i : findDup(arr)) {
			System.out.println(i);
		}
	}
}

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Find occurence once :

package com.algo.bits;

public class FindNumberWithOccurenceOne {
	public static int xorApproach(int[] inputArray)
	{
	    int result = 0;
	    for(int i=0;i<inputArray.length;i++)
	    {
	        result ^= inputArray[i];
	    }
	                    
	    return (result>0 ? result : -1);
	}
	
	public static void main(String[] args) {
		int[] arr = { 1, 2, 2,1, 3,2 };
		System.out.println(xorApproach(arr));
	}
}

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Unique Number :
package com.algo.bits;
class UniqueNumber{
    public static boolean isUnique( int n ){
        short status=0;
        byte digit;
        //System.out.println((2&4));
        for( int temp=n; temp>0; temp/=10 ){
            digit = (byte)(temp%10);
            
            if( (status & (1<<(digit))) >0 ) return false;
            else status |= 1<<(digit);
            
        }
        return true;
    }
    public static void main( String args[] ){
        System.out.println(isUnique(343)); //1234 is a unique number	
        //System.out.println(isUnique(12342));//12342 is not a unique number
    }
}