One round of technical interviews, one round of video technical interviews, and one round of HR interviews. The entire interview process is very fast. The interviews are separated by one or two days, but the interview results will have to wait for more than a week. Finally, the company will call the final interview results. Overall, Tencent’s interviews are highly efficient.

Q: The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n-queens puzzle. Each solution contains a distinct board configuration of the n-queens' placement, where 'Q' and '.' both indicate a queen and an empty space respectively.

Q: Throw n dice on the ground, and the sum of the points of all the dice facing up is s. Enter n to output the frequency at which all possible values ​​of s occur.