Keep Only the Highest Set Bit

Code

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

// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
/* Phuong an 1 dung vong lap
    int cnt=0;
    if(reg == 0){
        return 0;
    }else if(reg > 0){
        do{
           reg = (reg >> 1);
           cnt++; 
        }while(reg != 1);
    }
    return (1<<cnt);
*/
//phuong an 2 
    reg |= (reg >> 1);
    reg |= (reg >> 2);
    reg |= (reg>> 4);
    reg |= (reg >> 8);
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