Processes each line of the given Reader, returning the selected column for the
line where the absolute difference between the integer value of col1 and col2
is least.
Dave Thomas's Kata One asks us to think about how one might
implement pricing rules:
"Some things in supermarkets have simple prices: this can of
beans costs $0.65.
In practice, one would most likely use the
binary search method already available in
java.util.Collections, but that's not
really the point of this exercise.
One fun functional approach is to "slice" up the
list as we search, looking at smaller and
smaller slices until we've found the element
we're looking for.