In chemistry there is a type of extension, .xyz extension,(https://en.wikipedia.org/wiki/XYZ_file_format), that prints in each line a chemical element, and the coordinates in the plane of the element. This is very useful for chemists to understand chemical compounds and to visualize the compounds in 3D. I thought it would be fun to, given a .xyz file, print the chemical formula.
Given an .xyz file, print the chemical formula of the compound in any programming language in the smallest possible number of bytes. Note:
- Originally, the input was to be given as a file. As I have been pointed out, this constraints the challenge. Therefore you may assume the input is a list/array of strings, each representing a line of the .xyz file.
- There are no restrictions in the ordering of the elements.
- Each element should be printed with an underscore "_" delimiting the element and the number of times it appears
- The first two lines of any .xyz file is the number of elements, and a comment line (keep that in mind).
Example Input and Output
Suppose you have a file p.xyz which contains the following (where the first line is the number of elements, and the second a comment), input:
5 A mystery chemical formula... Ba 0.000 0.000 0.000 Hf 0.5 0.5 0.5 O 0.5 0.5 0.000 O 0.5 0.000 0.5 O 0.000 0.5 0.5
A quick test is with the example mentioned. A more thorough test is the following:
since the test file is thousands of lines, I'll share the .xyz file: