MathDB
BMT 2022 Guts #15

Source:

August 31, 2023
number theorycombinatorics

Problem Statement

Let f(x)f(x) be a function acting on a string of 00s and 11s, defined to be the number of substrings of xx that have at least one 11, where a substring is a contiguous sequence of characters in xx. Let SS be the set of binary strings with 2424 ones and 100100 total digits. Compute the maximum possible value of f(s)f(s) over all sSs\in S. For example, f(110)=5f(110) = 5 as 110\underline{1}10, 1101\underline{1}0, 110\underline{11}0, 1101\underline{10}, and 110\underline{110} are all substrings including a 11. Note that 11011\underline{0} is not such a substring.