Update 0474.一和零，添加C#

problems/0474.一和零.md

@@ -533,6 +533,33 @@ impl Solution {
     }
 }
 ```
+### C#
+```csharp
+public class Solution
+{
+    public int FindMaxForm(string[] strs, int m, int n)
+    {
+        int[,] dp = new int[m + 1, n + 1];
+        foreach (string str in strs)
+        {
+            int zero = 0, one = 0;
+            foreach (char c in str)
+            {
+                if (c == '0') zero++;
+                else one++;
+            }
+            for (int i = m; i >= zero; i--)
+            {
+                for (int j = n; j >= one; j--)
+                {
+                    dp[i, j] = Math.Max(dp[i, j], dp[i - zero, j - one] + 1);
+                }
+            }
+        }
+        return dp[m, n];
+    }
+}
+```
 
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