bit_manipulation Namespace Reference

for IO operations More...

Functions
bool	isPowerOfTwo (std ::int64_t n)
	The main function implements check for power of 2.

Detailed Description

for IO operations

Bit manipulation algorithms.

for io operations

storing the numbers

for assert

Bit manipulation algorithms

for assert for IO operations

Bit manipulation algorithms

for assert

Bit Manipulation algorithms

for std::min for assert for IO operations for limits of integral types for std::vector

Function Documentation

isPowerOfTwo()

bool bit_manipulation::isPowerOfTwo

(

std ::int64_t

n

)

The main function implements check for power of 2.

Parameters

n	is the number who will be checked

Returns

either true or false

                                 {  // int64_t is preferred over int so that
                                      // no Overflow can be there.
 
    return n > 0 && !(n & n - 1);  // If we subtract a power of 2 numbers by 1
    // then all unset bits after the only set bit become set; and the set bit
    // becomes unset.
 
    // If a number n is a power of 2 then bitwise and of n-1 and n will be zero.
    // The expression n&(n-1) will not work when n is 0.
    // To handle this case also, our expression will become n& (!n&(n-1))
}