ASU 250 All Soviet Union MO 1977 scales and weights, in n-letter word
Source:
July 6, 2019
combinatoricsWords
Problem Statement
Given scales and a set of different weights. We take weights in turn and add them on one of the scales sides. Let us denote "" the scales state with the left side down, and "" -- with the right side down. a) Prove that you can arrange the weights in such an order, that we shall obtain the sequence of the scales states. (That means that the state of the scales will be changed after putting every new weight.) b) Prove that for every -letter word containing 's and 's only you can arrange the weights in such an order, that the sequence of the scales states will be described by that word.