6.49 Five students $A, B, C, D, E$ participated in a competition. Two people, Jia and Yi, were guessing the results outside the venue. Jia guessed the ranking order to be $A B C D E$. However, he did not guess any of the participants' ranks correctly, nor did he guess the correct order of any adjacent participants (adjacent means the ranks are next to each other). Yi guessed the order to be $D A E C B$. This guess was much more accurate, as he not only guessed the ranks of two participants correctly but also the correct order of two pairs of adjacent participants. What is the ranking order of the competition results?
[Solution] It is easy to see that we should start from the result of Yi's guess. For this, we prove a more general result:

Lemma If two permutations of 5 elements $A B C D E$ and $F G H I J$ have exactly two elements in the same position and exactly two pairs of adjacent elements in the same order, then the two elements in the same position must be at one end, i.e., either $A=F, B=G$, or $D=I, E=J$.

If not, then either the two elements in the same position are adjacent but not at one end, or they are not adjacent. If the former case occurs, without loss of generality, let $B=G, C=H$, then the other pair of adjacent elements with the same order, whether it is $A B, C D$ or $D E$, will lead to at least 3 elements being in the same position, which is a contradiction. If the two elements in the same position are not adjacent, then at least one of them must be one of the two pairs of adjacent elements with the same order, thus leading to at least 3 elements being in the same position, which is a contradiction.

Let's return to solving the problem. From the result of Yi's guess and the above lemma, we know that the result of the competition must be one of the following 4 scenarios:
$D A C B E, D A B E C, E D A C B, A E D C B$.

Since $D A C B E$ and $A B C D E$ have $C, E$ in the same position, and $A E D C B$ and $A B C D E$ have $A$ in the same position, neither can be the result of the competition. And $D A B E C$ and $A B C D E$ have one pair of elements $A B$ in the same order, so it cannot be the result of the competition either. Therefore, the order of the competition result is $E D A C B$.