The atomic number(原子序数)is equal to the number of electrons per atom or, what is equivalent, the number of protons per nucleus(原子核).
Number of substrings having an equal number of lowercase and uppercase letters - In this problem, we need to count the total number of strings of the given string containing an equal number of lowercase and uppercase characters. The naïve approach to
If mathematicians were to use , or to say that is undefined, then the binomial theorem would continue to hold (in some form), though not as written above. In that case though the theorem would be more complicated because it would have to handle the special case of the term corresponding ...