I see equally many knights to my left and to my right, knights always tell truth
Source: 2019 RMM Shortlist C1
June 19, 2020
combinatorics
Problem Statement
Let and be integers such that and . A number of persons sit around the Round Table, equally spaced. Each person is either a knight (always telling the truth) or a liar (who always lies). Each person sees the nearest k persons clockwise, and the nearest persons anticlockwise. Each person says: ''I see equally many knights to my left and to my right." Establish, in terms of and , whether the persons around the Table are necessarily all knights.Sergey Berlov, Russia