n-queens-ii.md

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 the number of distinct solutions to the n-queens puzzle.

Example:

Input: 4 Output: 2 Explanation: There are two distinct solutions to the 4-queens puzzle as shown below. [ [".Q..", // Solution 1 "...Q", "Q...", "..Q."],

["..Q.", // Solution 2 "Q...", "...Q", ".Q.."] ]

My code:

class Solution:
    def totalNQueens(self, n):
        """
        :type n: int
        :rtype: int
        """
        self.count=0
        self.n=n
        self.DFS([],[],[])
        return self.count
    def DFS(self,quenes,xy_diff,xy_sum):
        p=len(quenes)
        #print('executing %d'%p)
        if len(quenes)==self.n:
            
            self.count+=1
            return
        for i in range(self.n):
            if i not in quenes and (i-p) not in xy_diff and (i+p) not in xy_sum:
                
                self.DFS(quenes+[i],xy_diff+[i-p],xy_sum+[i+p])
            

Solution: https://leetcode.com/problems/n-queens-ii/