Bitwise Algorithms

The Bitwise Algorithms are used to perform operations at bit-level or to manipulate bits in different ways. The bitwise operations are found to be much faster and are some times used to improve the efficiency of a program.

For example: To check if a number is even or odd. This can be easily done by using Bitwise-AND(&) operator. If the last bit of the operator is set than it is ODD otherwise it is EVEN. Therefore, if num & 1 not equals to zero than num is ODD otherwise it is EVEN.

Recent Articles on Bit Magic !

Topic :



Basic :

  1. Find the element that appears once
  2. Detect if two integers have opposite signs
  3. Add 1 to a given number
  4. Multiply a given Integer with 3.5
  5. Turn off the rightmost set bit
  6. Find whether a given number is a power of 4 or not
  7. Compute modulus division by a power-of-2-number
  8. Rotate bits of a number
  9. Find the Number Occurring Odd Number of Times
  10. Check for Integer Overflow
  11. Count set bits in an integer
  12. Count number of bits to be flipped to convert A to B
  13. Efficient way to multiply with 7
  14. Program to find whether a no is power of two
  15. Position of rightmost set bit
  16. Binary representation of a given number
  17. Find position of the only set bit
  18. How to swap two numbers without using a temporary variable?
  19. Swap two nibbles in a byte
  20. How to turn off a particular bit in a number?
  21. Russian Peasant (Multiply two numbers using bitwise operators)
  22. Add two bit strings
  23. Write your own strcmp that ignores cases
  24. Check if two numbers are equal without using arithmetic and comparison operators
  25. Find XOR of two number without using XOR operator

More >>

Intermediate :

  1. Swap bits in a given number
  2. Little and Big Endian Mystery
  3. Smallest of three integers without comparison operators
  4. A Boolean Array Puzzle
  5. Compute the integer absolute value (abs) without branching
  6. Compute the minimum or maximum of two integers without branching
  7. Find the two non-repeating elements in an array of repeating elements
  8. Write an Efficient C Program to Reverse Bits of a Number
  9. Smallest power of 2 greater than or equal to n
  10. Write a C program to find the parity of an unsigned integer
  11. Swap all odd and even bits
  12. Check if binary representation of a number is palindrome
  13. Generate n-bit Gray Codes
  14. Check if a given number is sparse or not
  15. Euclid’s Algorithm when % and / operations are costly
  16. Find nth Magic Number
  17. How to swap two bits in a given integer?
  18. Calculate square of a number without using *, / and pow()
  19. Generate 0 and 1 with 25% and 75% probability
  20. Find even occurring elements in an array of limited range
  21. Cyclic Redundancy Check and Modulo-2 Division
  22. Copy set bits in a range
  23. Check if a number is Bleak
  24. Count strings with consecutive 1’s
  25. Gray to Binary and Binary to Gray conversion

More >>

Hard :

  1. Count total set bits in all numbers from 1 to n
  2. Program to count number of set bits in an (big) array
  3. Next higher number with same number of set bits
  4. Karatsuba algorithm for fast multiplication
  5. Find the maximum subarray XOR in a given array
  6. Inserting m into n such that m starts at bit j and ends at bit i
  7. Find Duplicates of array using bit array
  8. Find longest sequence of 1’s in binary representation with one flip
  9. Closest (or Next) smaller and greater numbers with same number of set bits
  10. Bitmasking and Dynamic Programming | Set-2 (TSP)
  11. Compute the parity of a number using XOR and table look-up
  12. XOR Encryption by Shifting Plaintext
  13. Count pairs in an array which have at least one digit common
  14. Python program to convert floating to binary
  15. Levelwise Alternating OR and XOR operations in Segment Tree
  16. Booth’s Multiplication Algorithm
  17. Leftover element after performing alternate Bitwise OR and Bitwise XOR operations on adjacent pairs
  18. Number of pairs with Pandigital Concatenation
  19. Find the n-th number whose binary representation is a palindrome

Misc :

  1. Interesting Facts about Bitwise Operators in C
  2. Optimization Techniques | Set 1 (Modulus)
  3. What are the differences between bitwise and logical AND operators in C/C++?
  4. Bit Fields in C
  5. C++ bitset and its application
  6. C++ bitset interesting facts
  7. Builtin functions of GCC compiler
  8. Bits manipulation (Important tactics)
  9. Bit Tricks for Competitive Programming

Quick Links :

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.



My Personal Notes arrow_drop_up