The **N-Queens** puzzle is the problem of placing `n` queens on an `n x n` chessboard such that no two queens attack each other.
Given an integer `n`, return **all distinct solutions** to the N-Queens puzzle. You may return the answer in **any order**.
Each solution contains a distinct board configuration of the N-Queens' placement, where `'Q'` indicates a queen and `'.'` indicates an empty space.