Keep Only the Highest Set Bit

Code

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
    // Your logic here
   if (reg == 0) return 0;  // No bits set
    
    // Propagate the highest set bit to all lower positions
    reg |= reg >> 1;
    reg |= reg >> 2;
    reg |= reg >> 4;
    reg |= reg >> 8;
    
    // Subtract the right-shifted value to isolate only the highest bit
    return reg - (reg >> 1);
}

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

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

Solving Approach