P8248 Simple Sequence.

You are given an integer $n$. You need to construct an array $a$ of length $n$ (indices start from $1$, and each element is one of $1,2,3$ or $4$), such that: - For the $i$-th element, for all $1 \le len \le \lfloor\frac{i}{2}\rfloor$, the subarray $a_{i-len+1\dots i}$ is not equal to $a_{i-len\times2+1\dots i-len}$. ($\lfloor x \rfloor$ means rounding $x$ down.) - In plain words, there are no two adjacent consecutive substrings that are identical.

One line with one positive integer $n$.

One line with $n$ positive integers, the array $a$.

For $20\%$ of the testdata, $1 \le n \le 10$. For $40\%$ of the testdata, $1 \le n \le 30$. For $100\%$ of the testdata, $1 \le n \le 500$. Translated by ChatGPT 5