# =-=-=-= DAY 57 [Medium] =-=-=-=
#
# Given a string s and an integer k, break up the string into multiple lines such
# that each line has a length of k or less. You must break it up so that words
# don't break across lines. Each line has to have the maximum possible amount of
# words. If there's no way to break the text up, then return null.
# 
# You can assume that there are no spaces at the ends of the string and that there
# is exactly one space between each word.
# 
# For example, given the string "the quick brown fox jumps over the lazy dog" and
# k = 10, you should return: ["the quick", "brown fox", "jumps over", "the lazy",
# "dog"]. No string in the list has a length of more than 10.
