9. Keep Only the Highest Set Bit
Good approach. I just did a little change so that only the righmost set bit is removed in the next iteration.
uint16_t highest_set_bit1(uint16_t reg) {
if(reg == 0) return 0;
/*
(reg & (reg - 1) clears the lowest (rightmost) set bit of reg.
This expression is nonzero whenever reg contains more than one set bit.
*/
while(reg & (reg - 1)){
reg &= (reg - 1);
}
return reg;
}
#include <stdio.h>
#include <stdint.h>
// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
// Your logic here
int bit=0,temp,k=0;
while(bit <= 31)
{
temp = reg & (1<<bit);
if(k < temp)
{
k = temp;
}
bit++;
}
return k;
}
int main() {
uint16_t reg;
scanf("%hu", ®);
uint16_t result = highest_set_bit(reg);
printf("%hu", result);
return 0;
}
// Unique Solution Among All
// function
uint16_t highest_set_bit(uint16_t reg) {
uint16_t max = 0;
for (int i = 15; i >= 0; i--) {
uint16_t mask = 1 << i;
if (reg & mask) {
max = reg & mask;
break;
}
}
return max;
}
#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;
}
for (int i =15; i>=0; i--){
uint16_t mask = 1<<i;
if(reg & mask) {
return mask;
}
}
}
int main() {
uint16_t reg;
scanf("%hu", ®);
uint16_t result = highest_set_bit(reg);
printf("%hu", result);
return 0;
}
#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;
// Step 1: Smear bits to the right
reg |= (reg >> 1);
reg |= (reg >> 2);
reg |= (reg >> 4);
reg |= (reg >> 8);
// Step 2: Subtract the (reg >> 1) value form reg
return reg - (reg >> 1);
}
int main() {
uint16_t reg;
scanf("%hu", ®);
uint16_t result = highest_set_bit(reg);
printf("%hu", result);
return 0;
}
uint16_t highest_set_bit(uint16_t reg) {
int i;
int j = 0;
for (i = 15; i >= 0; i--)
{
if( reg & (1<<i))
{
reg = 0;
reg |= (1<<i);
return reg;
}
}
return reg;
}
uint16_t highest_set_bit(uint16_t reg) {
reg|=reg>>1;
reg|=reg>>2;
reg|=reg>>4;
reg|=reg>>8;
return reg&~(reg>>1);
}
O(1) time complexity
#include <stdio.h>
#include <stdint.h>
// Complete the function
uint16_t highest_set_bit(uint16_t reg) {
// Your logic here
for (int i = 15; i>=0 ; i--){
if ( reg & (1<< i)){
return reg &= (1<<i);
}
}
return 0;
}
int main() {
uint16_t reg;
scanf("%hu", ®);
uint16_t result = highest_set_bit(reg);
printf("%hu", result);
return 0;
}