From 69103f6c86fddc3d10ffe921dce8b93e259f71e2 Mon Sep 17 00:00:00 2001
From: eeee0717 <chentao020717Work@outlook.com>
Date: Sat, 23 Dec 2023 10:11:06 +0800
Subject: [PATCH] =?UTF-8?q?Update0051.N=E7=9A=87=E5=90=8E=EF=BC=8C?=
 =?UTF-8?q?=E6=B7=BB=E5=8A=A0C#?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 problems/0051.N皇后.md | 54 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/problems/0051.N皇后.md b/problems/0051.N皇后.md
index f6290793..1e108540 100644
--- a/problems/0051.N皇后.md
+++ b/problems/0051.N皇后.md
@@ -865,6 +865,60 @@ object Solution {
   }
 }
 ```
+### C#
+```csharp
+public class Solution
+{
+    public List<IList<string>> res = new();
+    public IList<IList<string>> SolveNQueens(int n)
+    {
+        char[][] chessBoard = new char[n][];
+        for (int i = 0; i < n; i++)
+        {
+            chessBoard[i] = new char[n];
+            for (int j = 0; j < n; j++)
+            {
+                chessBoard[i][j] = '.';
+            }
+        }
+        BackTracking(n, 0, chessBoard);
+        return res;
+    }
+    public void BackTracking(int n, int row, char[][] chessBoard)
+    {
+        if (row == n)
+        {
+            res.Add(chessBoard.Select(x => new string(x)).ToList());
+            return;
+        }
+        for (int col = 0; col < n; col++)
+        {
+            if (IsValid(row, col, chessBoard, n))
+            {
+                chessBoard[row][col] = 'Q';
+                BackTracking(n, row + 1, chessBoard);
+                chessBoard[row][col] = '.';
+            }
+        }
+    }
+    public bool IsValid(int row, int col, char[][] chessBoard, int n)
+    {
+        for (int i = 0; i < row; i++)
+        {
+            if (chessBoard[i][col] == 'Q') return false;
+        }
+        for (int i = row - 1, j = col - 1; i >= 0 && j >= 0; i--, j--)
+        {
+            if (chessBoard[i][j] == 'Q') return false;
+        }
+        for (int i = row - 1, j = col + 1; i >= 0 && j < n; i--, j++)
+        {
+            if (chessBoard[i][j] == 'Q') return false;
+        }
+        return true;
+    }
+}
+```
 
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