Can anyone give me some links through which I can learn siblings dp? And also please provide me some problems related to it. Thanks in advanced...

I am trying to solve this problem for this input. My code is here. My codeblocks compiler gives output 3. And also a online compiler "ideone" (code) gives output 3. But in my submission it gives output 2. I don't know why this kind different output in different compilers. Please anyone help me. Thanks in advanced.