题解 | #N皇后问题#

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param n int整型 the n
# @return int整型
#
class Solution:
    def dps(self, i,n,has):
        fob = {}
        for item in has:
            x,y = item
            fob[y]=1
            fob[y+i-x]=1
            fob[y-(i-x)]=1
        for j in range(n):
            if j not in fob.keys():
                hasnew=has+[(i,j)]
                if i==n-1:
                    self.all.append(hasnew)
                else:
                    self.dps(i+1,n,hasnew)
        
        return 0
               
    def Nqueen(self , n: int) -> int:
        # write code here
        self.all= []
        self.dps(0,n,[])
        return len(self.all)