Update 0435.无重叠区间，添加C#

problems/0435.无重叠区间.md

@@ -441,6 +441,27 @@ impl Solution {
     }
 }
 ```
+### C#
+```csharp
+public class Solution
+{
+    public int EraseOverlapIntervals(int[][] intervals)
+    {
+        if (intervals.Length == 0) return 0;
+        Array.Sort(intervals, (a, b) => a[1].CompareTo(b[1]));
+        int res = 1, end = intervals[0][1];
+        for (int i = 1; i < intervals.Length; i++)
+        {
+            if (end <= intervals[i][0])
+            {
+                end = intervals[i][1];
+                res++;
+            }
+        }
+        return intervals.Length - res;
+    }
+}
+```
 
 
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