distance between two 5-digit numbers
Source: Indian Postal Coaching 2007 set 3 p6
May 25, 2020
number theorySum
Problem Statement
Define the distance between two -digit numbers and to be the largest integer such that . (Example: the distance between and is .) Suppose all -digit numbers are written in a line in some order. What is the minimal possible sum of the distances of adjacent numbers in that written order?