From db6caf0d438021f59abd8ff3809705b2ce170960 Mon Sep 17 00:00:00 2001
From: krahets <krahets@163.com>
Date: Fri, 5 May 2023 03:42:01 +0800
Subject: [PATCH] Update n queens.

---
 codes/java/chapter_backtracking/n_queens.java | 42 +++++++++----------
 mkdocs.yml                                    |  2 +-
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/codes/java/chapter_backtracking/n_queens.java b/codes/java/chapter_backtracking/n_queens.java
index b9a7e7702..6705ebc16 100644
--- a/codes/java/chapter_backtracking/n_queens.java
+++ b/codes/java/chapter_backtracking/n_queens.java
@@ -9,27 +9,6 @@ package chapter_backtracking;
 import java.util.*;
 
 public class n_queens {
-    /* 求解 N 皇后 */
-    public static List<List<List<String>>> nQueens(int n) {
-        // 初始化 n*n 大小的棋盘，其中 'Q' 代表皇后，'#' 代表空位
-        List<List<String>> state = new ArrayList<>();
-        for (int i = 0; i < n; i++) {
-            List<String> row = new ArrayList<>();
-            for (int j = 0; j < n; j++) {
-                row.add("#");
-            }
-            state.add(row);
-        }
-        boolean[] cols = new boolean[n]; // 记录列是否有皇后
-        boolean[] diags1 = new boolean[2 * n - 1]; // 记录主对角线是否有皇后
-        boolean[] diags2 = new boolean[2 * n - 1]; // 记录副对角线是否有皇后
-        List<List<List<String>>> res = new ArrayList<>();
-
-        backtrack(0, n, state, res, cols, diags1, diags2);
-
-        return res;
-    }
-
     /* 回溯算法：N 皇后 */
     public static void backtrack(int row, int n, List<List<String>> state, List<List<List<String>>> res,
             boolean[] cols, boolean[] diags1, boolean[] diags2) {
@@ -61,6 +40,27 @@ public class n_queens {
         }
     }
 
+    /* 求解 N 皇后 */
+    public static List<List<List<String>>> nQueens(int n) {
+        // 初始化 n*n 大小的棋盘，其中 'Q' 代表皇后，'#' 代表空位
+        List<List<String>> state = new ArrayList<>();
+        for (int i = 0; i < n; i++) {
+            List<String> row = new ArrayList<>();
+            for (int j = 0; j < n; j++) {
+                row.add("#");
+            }
+            state.add(row);
+        }
+        boolean[] cols = new boolean[n]; // 记录列是否有皇后
+        boolean[] diags1 = new boolean[2 * n - 1]; // 记录主对角线是否有皇后
+        boolean[] diags2 = new boolean[2 * n - 1]; // 记录副对角线是否有皇后
+        List<List<List<String>>> res = new ArrayList<>();
+
+        backtrack(0, n, state, res, cols, diags1, diags2);
+
+        return res;
+    }
+
     public static void main(String[] args) {
         int n = 4;
         List<List<List<String>>> res = nQueens(n);
diff --git a/mkdocs.yml b/mkdocs.yml
index 785b0102b..56017ca4e 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -190,7 +190,7 @@ nav:
   - 13. &nbsp; &nbsp; 回溯算法:
     - 13.1. &nbsp; 回溯算法（New）: chapter_backtracking/backtracking_algorithm.md
     - 13.2. &nbsp; 全排列问题（New）: chapter_backtracking/permutations_problem.md
-    - 13.3. &nbsp; n 皇后问题（New）: chapter_backtracking/n_queens_problem.md
+    - 13.3. &nbsp; N 皇后问题（New）: chapter_backtracking/n_queens_problem.md
   - 14. &nbsp; &nbsp; 附录:
     - 14.1. &nbsp; 编程环境安装: chapter_appendix/installation.md
     - 14.2. &nbsp; 一起参与创作: chapter_appendix/contribution.md