Playing with Kth bit

1) Turn Off k^th bit in a number

int turnOffKthBit(int n, int k) {
    return n & ~(1 << (k - 1));
}

2) Turn On k^th bit in a number

int turnOnKthBit(int n, int k) {
    return n | (1 << (k - 1));
}

3) Check if k^th bit is set for a number

bool isKthBitSet(int n, int k) {
    return (n & (1 << (k - 1))) != 0;
}

4) Toggle the k^th bit

int toggleKthBit(int n, int k) {
    return n ^ (1 << (k - 1));
}

Please refer this article for more bit hacks.


 

In competitive programming or in general, some problems seem difficult but can be solved very easily with little concepts of bit magic. We have discussed some tricks below in the previous post.
Bitwise Hacks for Competitive Programming