3.41 Two postal codes $M$ and $N$ on an envelope are both composed of the 6 different digits $0,1,2,3,5,6$. There are 4 postal codes as follows:
$$
\begin{array}{l}
A: 320651, \quad B: 105263, \\
C: 612305, \quad D: 316250 .
\end{array}
$$

It is known that codes $A, B, C$ each have exactly two digits in the same position as $M, N$, and $D$ has exactly 3 digits in the same position as $M, N$. Try to find the codes $M$ and $N$.
[Solution] According to the given information, $A, B, C$ each have exactly two digits the same as $M, N$, and $D$ has exactly 3 digits the same as $M, N$. Therefore, $M$ and $N$ each have 9 digits that are in the same position as one of $A, B, C, D$ (including repetitions). From the table, it can be seen that any digit in $M, N$ is at most the same as two positions in $A, B, C, D$. Hence, each of the 6 digits in $M, N$ has exactly 3 digits that are the same as two positions in $A, B, C, D$. Clearly, these 3 digits can only be the 3 in the first column, the 1 in the second column, the 2 in the fourth column, and the 5 in the fifth column, of which 3 are chosen.
(1) Let the required code be $x \mid 1] y[2] 5 \mid z$. Placing this code in the blank spaces of the previous table, $x, y, z$ should each be the same as one of the first 3 digits in their respective columns, but they cannot be the same as the 4th digit in their respective columns. $x$ cannot be 3 and 1, so it can only be $6; y$ cannot be $6,2,5$, so it can only be $0; z=3$. Thus, we obtain a code that meets the requirements: 610253.
(2) Let the required code be $3|a| b|2| 5 \mid c$. Analyzing similarly to (1), $a$ cannot be 1,2, so it can only be $0; b$ cannot be $0,5,2,6$, which is a contradiction.
(3) Let the required code be $3[1|d| e] 5[f]$. It is easy to see that $f$ cannot be $1,3,5,0$, which is a contradiction.
(4) Let the required code be $3[1|k| 2|m| n$. It is easy to see that $n$ cannot be $1,3,0$, so it can only be $5; k$ cannot be $5,2,6$, so it can only be 0. Thus, $m=6$. Therefore, we obtain another code that meets the requirements: 310265.
In summary, the required $M$ and $N$ are 610253 and 310265, respectively.