Block Cipher Mode of Operations
It is a block cipher with block size 3. Therefore for a given known-plaintext, we can build the current key's action table that has $2^3=8$ values. We will use the decryption part $$P_i = D(C_i) \oplus C_{i-1} \oplus P_{i-1}$$ with $C_{0} \oplus P_{0} = IV$ with conversion
$$D(C_i) = P_i \oplus C_{i-1} \oplus P_{i-1}$$
P_i          000 001 010 011 100 101 110 111
P_i-1        ??? 000 001 010 011 100 101 110
C_i-1        ??? 111 110 101 100 011 001 000
--- xor-all
x-ored       ??? 110 101 100 011 010 010 001 
C_i          111 110 101 100 011 001 000 010

Now built the decryption table and the encryption table is just the reverse of it.
$$\begin{array}{|c|c|}\hline
\text{input} &amp; \text{output} \\ \hline
\texttt{000} &amp; \color{red}{\texttt{010}}\\ \hline
\texttt{001} &amp; \color{red}{\texttt{010}}\\ \hline
\texttt{010} &amp; \texttt{001}\\ \hline
\texttt{011} &amp; \texttt{011}\\ \hline
\texttt{100} &amp; \texttt{100}\\ \hline
\texttt{101} &amp; \texttt{101}\\ \hline
\texttt{110} &amp; \texttt{110}\\ \hline
\texttt{111} &amp; \texttt{???}\\ \hline
\end{array}$$
With the current information, this question is not solvable since the defined block cipher is not reversible. The PCBC mode requires this.
P.S. Maybe I had a mistake with the simple calculations. If so inform me please;