Bit Rotation: A rotation (or circular shift) is an operation similar to a shift except that the bits that fall off at one end are put back to the other end.
In the left rotation, the bits that fall off at the left end are put back at the right end.
In the right rotation, the bits that fall off at the right end are put back at the left end.
Example:
Let n is stored using 8 bits. Left rotation of n = 11100101 by 3 makes n = 00101111 (Left shifted by 3 and first 3 bits are put back in last ). If n is stored using 16 bits or 32 bits then left rotation of n (000…11100101) becomes 00..0011100101000.
Right rotation of n = 11100101 by 3 makes n = 10111100 (Right shifted by 3 and last 3 bits are put back in first ) if n is stored using 8 bits. If n is stored using 16 bits or 32 bits then right rotation of n (000…11100101) by 3 becomes 101000..0011100.
Java
// Java code to rotate bits // of numberclass GFG {static final int INT_BITS = 32;/*Function to left rotate n by d bits*/static int leftRotate(int n, int d) { /* In n<<d, last d bits are 0. To put first 3 bits of n at last, do bitwise or of n<<d with n >>(INT_BITS - d) */ return (n << d) | (n >> (INT_BITS - d));}/*Function to right rotate n by d bits*/static int rightRotate(int n, int d) { /* In n>>d, first d bits are 0. To put last 3 bits of at first, do bitwise or of n>>d with n <<(INT_BITS - d) */ return (n >> d) | (n << (INT_BITS - d));}// Driver codepublic static void main(String arg[]) { int n = 16; int d = 2; System.out.print("Left Rotation of " + n + " by " + d + " is "); System.out.print(leftRotate(n, d)); System.out.print("Right Rotation of " + n + " by " + d + " is "); System.out.print(rightRotate(n, d));}}// This code is contributed by Anant Agarwal. |
Output :
Left Rotation of 16 by 2 is 64 Right Rotation of 16 by 2 is 4
Time Complexity: O(1)
Auxiliary Space: O(1)
For 16 bit number:
Java
import java.io.*;class GFG { public static void main(String[] args) { int N = 28; int D = 2; rotate(N, D); } static void rotate(int N, int D) { // your code here int t = 16; int left = ((N << D) | N >> (t - D)) & 0xFFFF; int right = ((N >> D) | N << (t - D)) & 0xFFFF; System.out.println(left); System.out.println(right); }} |
Output:
Left Rotation of 28 by 2 is 112 Right Rotation of 28 by 2 is 7
Time Complexity : O(1)
Auxiliary Space: O(1)
Please refer complete article on Rotate bits of a number for more details!
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