Keep Only the Highest Set Bit

Code

#include <stdio.h>
#include <stdint.h>

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    while( reg & (reg - 1)){
        reg = reg & (reg - 1);
    }
    return reg;
}

int main() {
    uint16_t reg;
    scanf("%hu", &reg);

    uint16_t result = highest_set_bit(reg);
    printf("%hu", result);
    return 0;
}

Solving Approach

• Loop while more than one bit is set: reg & (reg - 1)
• In each iteration, clear the lowest set bit: reg = reg & (reg - 1)
• When only the highest bit remains, exit loop.
• Return reg → contains only the highest set bit.