Given a non-negative number n and two values l and r. The problem is to unset the bits in the range l to r in the binary representation of n, i.e, to unset bits from the rightmost lth bit to the rightmost rth bit.
Constraint: 1 <= l <= r <= number of bits in the binary representation of n.
Input : n = 42, l = 2, r = 5 Output : 32 (42)10 = (101010)2 (32)10 = (100000)2 The bits in the range 2 to 5 in the binary representation of 42 have been unset. Input : n = 63, l = 1, r = 4 Output : 48
Approach: Following are the steps:
- Calculate num = (1 << (sizeof(int) * 8 – 1)) – 1. This will produce the highest positive integer num. All the bits in num will be set.
- Toggle bits in the range l to r in num. Refer this post.
- Now, perform n = n & num. This will unset the bits in the range l to r in n.
- Return n.
Note: The sizeof(int) has been used as input is of int data type. For large inputs you can use long int or long long int datatypes in place of int.
This article is contributed by Ayush Jauhari. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. 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.
- Write an Efficient C Program to Reverse Bits of a Number
- Count set bits in an integer
- Count number of bits to be flipped to convert A to B
- Rotate bits of a number
- Next higher number with same number of set bits
- Program to count number of set bits in an (big) array
- Count total set bits in all numbers from 1 to n
- Swap bits in a given number
- Swap all odd and even bits
- Toggle all the bits of a number except k-th bit.
- Copy set bits in a range
- Find even occurring elements in an array of limited range
- Print first n numbers with exactly two set bits
- Check if bits of a number has count of consecutive set bits in increasing order
- Bitwise and (or &) of a range