Knights and scoundrels 2
Source: ItaMO 2012, P3
May 21, 2012
inductioncombinatorics proposedcombinatorics
Problem Statement
Let be an integer greater than or equal to . There are people in one line, each of which is either a scoundrel (who always lie) or a knight (who always tells the truth). Every person, except the first, indicates a person in front of him/her and says "This person is a scoundrel" or "This person is a knight." Knowing that there are strictly more scoundrel than knights, seeing the statements show that it is possible to determine each person whether he/she is a scoundrel or a knight.