44// #2024_11_11_Time_1_ms_(99.77%)_Space_44.8_MB_(61.16%) 
55
66import  java .util .ArrayList ;
7+ import  java .util .LinkedList ;
78import  java .util .List ;
89
910public  class  Solution  {
10-     public  static   List <List <String >> solveNQueens (int  n ) {
11+     public  List <List <String >> solveNQueens (int  n ) {
1112        char [][] board  = new  char [n ][n ];
1213        for  (int  i  = 0 ; i  < n ; i ++) for  (int  j  = 0 ; j  < n ; j ++) board [i ][j ] = '.' ;
1314        List <List <String >> res  = new  ArrayList <List <String >>();
14-         int   leftRow []  = new  int [n ];
15-         int   upperDiagonal []  = new  int [2  * n  - 1 ];
16-         int   lowerDiagonal []  = new  int [2  * n  - 1 ];
15+         int []  leftRow  = new  int [n ];
16+         int []  upperDiagonal  = new  int [2  * n  - 1 ];
17+         int []  lowerDiagonal  = new  int [2  * n  - 1 ];
1718        solve (0 , board , res , leftRow , lowerDiagonal , upperDiagonal );
1819        return  res ;
1920    }
@@ -22,9 +23,9 @@ void solve(
2223            int  col ,
2324            char [][] board ,
2425            List <List <String >> res ,
25-             int   leftRow [] ,
26-             int   lowerDiagonal [] ,
27-             int   upperDiagonal [] ) {
26+             int []  leftRow ,
27+             int []  lowerDiagonal ,
28+             int []  upperDiagonal ) {
2829        if  (col  == board .length ) {
2930            res .add (construct (board ));
3031            return ;
@@ -48,9 +49,9 @@ void solve(
4849    }
4950
5051    List <String > construct (char [][] board ) {
51-         List <String > res  = new  LinkedList <String >();
52-         for  (int   i  =  0 ;  i  <  board . length ;  i ++ ) {
53-             String  s  = new  String (board [ i ] );
52+         List <String > res  = new  LinkedList <>();
53+         for  (char []  chars  :  board ) {
54+             String  s  = new  String (chars );
5455            res .add (s );
5556        }
5657        return  res ;
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