From dcc37da6034f3ad8166c9f06ee2ab75a3ad204e7 Mon Sep 17 00:00:00 2001
From: eeee0717 <chentao020717Work@outlook.com>
Date: Thu, 14 Dec 2023 10:01:34 +0800
Subject: [PATCH] =?UTF-8?q?Update0039.=E7=BB=84=E5=90=88=E7=BB=BC=E5=90=88?=
 =?UTF-8?q?=EF=BC=8C=E6=B7=BB=E5=8A=A0C#?=
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---
 problems/0039.组合总和.md | 60 +++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/problems/0039.组合总和.md b/problems/0039.组合总和.md
index 37d5614e..81558cc1 100644
--- a/problems/0039.组合总和.md
+++ b/problems/0039.组合总和.md
@@ -598,6 +598,66 @@ object Solution {
   }
 }
 ```
+### C#
+```csharp
+public class Solution
+{
+    public IList<IList<int>> res = new List<IList<int>>();
+    public IList<int> path = new List<int>();
+    public IList<IList<int>> CombinationSum(int[] candidates, int target)
+    {
+        BackTracking(candidates, target, 0, 0);
+        return res;
+    }
+    public void BackTracking(int[] candidates, int target, int start, int sum)
+    {
+        if (sum > target) return;
+        if (sum == target)
+        {
+            res.Add(new List<int>(path));
+            return;
+        }
+        for (int i = start; i < candidates.Length; i++)
+        {
+            sum += candidates[i];
+            path.Add(candidates[i]);
+            BackTracking(candidates, target, i, sum);
+            sum -= candidates[i];
+            path.RemoveAt(path.Count - 1);
+        }
+    }
+}
+
+// 剪枝优化
+public class Solution
+{
+    public IList<IList<int>> res = new List<IList<int>>();
+    public IList<int> path = new List<int>();
+    public IList<IList<int>> CombinationSum(int[] candidates, int target)
+    {
+        Array.Sort(candidates);
+        BackTracking(candidates, target, 0, 0);
+        return res;
+    }
+    public void BackTracking(int[] candidates, int target, int start, int sum)
+    {
+        if (sum > target) return;
+        if (sum == target)
+        {
+            res.Add(new List<int>(path));
+            return;
+        }
+        for (int i = start; i < candidates.Length && sum + candidates[i] <= target; i++)
+        {
+            sum += candidates[i];
+            path.Add(candidates[i]);
+            BackTracking(candidates, target, i, sum);
+            sum -= candidates[i];
+            path.RemoveAt(path.Count - 1);
+        }
+    }
+}
+```
 
 
 <p align="center">