#+ANKI_DECK: study_deck_02 * TODO 0051. N Queens :hard: :PROPERTIES: :NEETCODE: [[file:../../roadmap.org::*0051. N Queens][0051. N Queens]] :END: 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'~ and ~'.'~ both indicate a queen and an empty space, respectively. *Example 1:* #+begin_src Input: n = 4 Output: [[".Q..","...Q","Q...","..Q."],["..Q.","Q...","...Q",".Q.."]] Explanation: There exist two distinct solutions to the 4-queens puzzle as shown above #+end_src *Example 2:* #+begin_src Input: n = 1 Output: [["Q"]] #+end_src *Constraints:* - ~1 <= n <= 9~ ** TODO Approach Write your approach here. ** TODO Python #+begin_src python :lc-problem 51 :lc-lang python3 class Solution: def solveNQueens(self, n: int) -> List[List[str]]: #+end_src ** TODO C++ #+begin_src cpp :lc-problem 51 class Solution { public: vector> solveNQueens(int n) { } }; #+end_src