O(1)_Operation_For_Some_Functions.md

O(1) Operation For Some Functions

EVEN & ODD

System.out.println((a & 1) == 0 ?  "EVEN" : "ODD" );

Multiply by 2 OR Division by 2

n = n << 1;   // Multiply n with 2
n = n >> 1;   // Divide n by 2

Swapping of 2 numbers

a ^= b;
b ^= a;
a ^= b; 

Calculating the number of digits

int count = (int) Math.floor(Math.log10(N)) + 1;

Efficient trick to know if a number is a power of 2

/* Method to check if x is power of 2*/
static boolean isPowerOfTwo (int x)
{
	/* First x in the below expression is	for the case when x is 0 */
	return x!=0 && ((x&(x-1)) == 0);
}