Test result fails for my code of Inspect Bits function - c

Question

Below code is for a test sample given in https://www.testdome.com/for-developers/solve-question/9780
The question is: Implement the inspect_bits function that checks if given number contains 2 or more consecutive ones in its binary representation. If it does, the function should return 1. Otherwise, it should return 0.
For example, inspect_bits(13) should return 1 as it contains 2 consecutive ones in its binary representation (1101).
My code is:
#include <stdlib.h>
#include <stdio.h>
int inspect_bits(unsigned int number)
{
unsigned int ref = 1;
int comp;
for (int i = 0; i< sizeof(number) * 8; i++)
{
int a = number& (ref << i);
printf("%d: a is %d\n", i, a);
int b = number& (ref << (i + 1));
printf("%d: b is %d\n", i, b);
if ((a != 0) && (b != 0))
{
return 1;
}
}
return 0;
}
#ifndef RunTests
int main()
{
printf("%d", inspect_bits(13));
}
#endif
The result seems ok, but the system tells:
Various numbers: Wrong answer
Can you help to modify my code?
Regards

Answer 1

To be honest, I think it's an issue with the test site itself. Your code returns the proper results for each test case given to it, and I even modified the code as such:
int inspect_bits(unsigned int number)
{
for (int i = 0; i < sizeof(number) * 8; ++i) {
if (((number & (1 << i)) != 0) && ((number & (1 << (i + 1))) != 0)) {
return 1;
}
}
return 0;
}
The test cases return 1 where there are 2 binary values together and works for 3 and above; however, running this code on the test site and it gives the error that the Various Numbers test fails.
Interestingly, using this code:
int inspect_bits(unsigned int number)
{
while (number >= 3) {
if ((number & 3) == 3) { return 1; }
number >>= 1;
}
return 0;
}
Which does basically the same thing, only using bit-shifting on a single number, and the test passes 100% ..
You could submit an e-mail explaining the error; but beyond that, I'm not sure what else it could be.
Hope that helps.

Answer 2

int flag = 0;
int inspect_bits(unsigned int number)
{
int *arr;
int i = 0;
number = convert(number);
while(number)
{
arr[i] = number % 10;
number /= 10;
i++;
}
for(int j = 0; j < i-1; j++)
{
if(arr[j] == arr[j+1])
{
flag = 1;
return flag;
}
}
return flag;
}
int convert (int num)
{
if(num == 0)
{
return 0;
}
else
{
return (num % 2 + 10 * convert(num / 2));
}
}
This is what I did and it said Various Words: Wrong Answer. It appears to be an issue with the test site. Some other questions on their site evaluates questions incorrectly. The ones that I've come across are all C programs. C++ works fine in my experience.

Answer 3

By my experience in testdome almost any exercise right solution has to do with efficiency of the algorithm
This code worked for me:
#include <stdlib.h>
#include <stdio.h>
int inspect_bits( unsigned int number ) {
do {
if( ( number&3 )==3 ) return 1;
} while( number>>=1 );
return 0;
}
#ifndef RunTests
int main () {
printf( "%d", inspect_bits( 13 ) );
}
#endif
In the code you posted, the for loop checks all the bits from the function's input argument 'number'. That's not enough efficient.
The point is that we don't have to wait until the complete number has been completely right shifted.
They say, we must check if there are 2 or more consecutive ones in its binary representation, in other words, function returns 1 if a minimum of 2 consecutive bits with value 1 are found, and the fewer value with 2 consecutive ones is a decimal 3 ( 3 = 0b00000011 ).
So we are able to check it comparing the number with 3 using an AND gate, and right shift to 'number' until it happens.
Let's take a different number than the example's one:
221 = 0b11011101 we just only need to compare 3 times and shift it 2 times.
0b11011101 (221)
& 0b00000011 ( 3)
------------------
= 0b00000001 ( 1)
0b11011101(221) >> 1 = 0b01101110(110)
0b01101110 (110)
& 0b00000011 ( 3)
------------------
= 0b00000010 ( 2)
0b01101110(110) >> 1 = 0b00110111(55)
0b00110111 (55)
& 0b00000011 ( 3)
------------------
= 0b00000011 ( 3) ----> FOUND! return 1