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
In words, that means that the value of is whatever approaches as the real number z gets smaller and smaller approaching the value x arbitrarily closely. [Clarification: a reader asked how it is possible that we can use in our definition of , which seems to be recursive. The reason it is...