1963 IMO 第 6 题

Five students $A, B, C, D$, and $E$ have taken part in a certain competition. Before the competition, two persons $X$ and $Y$ tried to guess the rankings. $X$ thought that the ranking would be $A, B, C, D, E$; and $Y$ thought that the ranking would be $D, A, E, C, B$. At the end, it was revealed that $X$ didn't guess correctly any rankings of the participants, and moreover, didn't guess any of the orderings of pairs of consecutive participants. On the other hand, $Y$ guessed the correct rankings of two participants and the correct ordering of two pairs of consecutive participants. Determine the rankings of the competition.

五名学生$A、B、C、D$和$E$参加了某项比赛。比赛前，$X$和$Y$两个人尝试猜测排名。 $X$认为排名是$A、B、C、D、E$；而$Y$认为排名是$D、A、E、C、B$。最后，我们发现$X$没有正确猜出参与者的任何排名，而且没有猜出连续参与者对的任何顺序。另一方面，$Y$ 猜测了两个参与者的正确排名以及两对连续参与者的正确排序。确定比赛名次。