Update README.md

Author: yanglbme

solution/2900-2999/2981.Find Longest Special Substring That Occurs Thrice I/README.md

@@ -271,9 +271,9 @@ function maximumLength(s: string): number {
 
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-### Solution 2: Counting
+### 方法二：计数
 
-The time complexity is $O(n)$
+时间复杂度 $O(n)$。
 
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