Binary
Study links
Notes
Questions involving binary representations and bitwise operations are asked sometimes and you must be absolutely familiar with how to convert a number from decimal form into binary form (and vice versa) in your chosen programming language.
Some helpful utility snippets:
- Test kth bit is set:
num & (1 << k) != 0. - Set kth bit:
num |= (1 << k). - Turn off kth bit:
num &= ~(1 << k). - Toggle the kth bit:
num ^= (1 << k). - To check if a number is a power of 2,
num & num - 1 == 0.
Corner cases
- Be aware and check for overflow/underflow
- Negative numbers