52N Queen II

Title: Given an integer n , returns the n number of different solutions of the queen.

Source: https: //leetcode-cn.com/problems/n-queens-ii/

Act One: your own code more than 90 percent

Ideas: calculated odd and even, respectively, the even symmetry direct use, in particular to calculate the intermediate odd-numbered row of the first column

class Solution:
     DEF totalNQueens (Self, n-: int) -> int: 
        Results = [0]
         DEF BackTrack (half_col, Row = -1, COL = 0,):
             # back termination condition, if the last line, indicating to find a solution of the stored 
            IF Row. 1-n-== :
                 # solution = [] 
                # for _, in the sorted COL (Queens): 
                #      '.' solution.append (COL * + 'Q' * + (n-'.' - COL -. 1)) 
                # results.append (Solution) 
                # Print (Results) 
                Results [0] = Results [0] +. 1 return 
            Row + =. 1
             IF (Row ==
                0):
                 # First Due to the symmetry line, so that when n is an odd number, only half of the traversing column 
                for COL in half_col:
                     IF cols [COL] + P [COL + Row] + Q [COL-Row] == 0: 
                        queens.add ((Row, COL)) 
                        cols [COL] =. 1 
                        P [COL + Row]. 1 = 
                        Q [COL -ROW] =. 1 
                        BackTrack (half_col, Row, COL) 
                        queens.remove ((Row, COL)) 
                        cols [COL] = 0 
                        P [COL + Row] = 0 
                        Q [COL- Row] = 0
             the else :
                 for COL in Range (n-):
                     IF cols [COL] + P [COL + Row] + Q [COL-Row] == 0: 
                        queens.add ((Row, COL)) 
                        cols [ COL] =. 1 
                        P [COL + Row]. 1 = 
                        Q [COL -ROW]. 1 =
                         # transferred to note here special parameters, positional parameters must pass 
                        # BackTrack (Row, COL) which is the original writing error 
                        backtrack (half_col, row , COL) 
                        queens.remove ((Row, COL)) 
                        cols [COL] = 0
                        P [COL + Row] = 0 
                        Q [COL - Row] = 0 
        cols = [0] * n- 
        P = [0] * (2 * n--. 1 ) 
        Q = [0] * (2 * n--. 1 ) 
        Queens = SET ()
         iF n% 2 == 0: 
            BackTrack (half_col = Range (int (n / 2 )))
             return Results [0] * 2
         # after the time when n is odd, been traversed half of the column, but also traversing the column intermediate 
        the else : 
            BackTrack (half_col = Range (int (n-/ 2 ))) 
            Results [0]Results = [0] * 2
             # Note that n is an odd number, the middle number is int (n / 2) 
            BackTrack (half_col = [int (n / 2 )])
             return Results [0]
 IF  the __name__ == ' __main__ ' : 
    duixiang = Solution () 
    WW = duixiang.totalNQueens (. 1 )
     Print ( ' result: ' , WW)

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