{ "data": { "question": { "questionId": "1363", "questionFrontendId": "2309", "categoryTitle": "Algorithms", "boundTopicId": 403669, "title": "Greatest English Letter in Upper and Lower Case", "titleSlug": "greatest-english-letter-in-upper-and-lower-case", "content": "

Given a string of English letters s, return the greatest English letter which occurs as both a lowercase and uppercase letter in s. The returned letter should be in uppercase. If no such letter exists, return an empty string.

\n\n

An English letter b is greater than another letter a if b appears after a in the English alphabet.

\n\n

 

\n

Example 1:

\n\n
\nInput: s = "lEeTcOdE"\nOutput: "E"\nExplanation:\nThe letter 'E' is the only letter to appear in both lower and upper case.\n
\n\n

Example 2:

\n\n
\nInput: s = "arRAzFif"\nOutput: "R"\nExplanation:\nThe letter 'R' is the greatest letter to appear in both lower and upper case.\nNote that 'A' and 'F' also appear in both lower and upper case, but 'R' is greater than 'F' or 'A'.\n
\n\n

Example 3:

\n\n
\nInput: s = "AbCdEfGhIjK"\nOutput: ""\nExplanation:\nThere is no letter that appears in both lower and upper case.\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "兼具大小写的最好英文字母", "translatedContent": "

给你一个由英文字母组成的字符串 s ，请你找出并返回 s 中的 最好 英文字母。返回的字母必须为大写形式。如果不存在满足条件的字母，则返回一个空字符串。

\n\n

最好 英文字母的大写和小写形式必须 都 在 s 中出现。

\n\n

英文字母 b 比另一个英文字母 a 更好 的前提是：英文字母表中，b 在 a 之 后 出现。

\n\n

 

\n\n

示例 1：

\n\n
\n输入：s = \"lEeTcOdE\"\n输出：\"E\"\n解释：\n字母 'E' 是唯一一个大写和小写形式都出现的字母。
\n\n

示例 2：

\n\n
\n输入：s = \"arRAzFif\"\n输出：\"R\"\n解释：\n字母 'R' 是大写和小写形式都出现的最好英文字母。\n注意 'A' 和 'F' 的大写和小写形式也都出现了，但是 'R' 比 'F' 和 'A' 更好。\n
\n\n

示例 3：

\n\n
\n输入：s = \"AbCdEfGhIjK\"\n输出：\"\"\n解释：\n不存在大写和小写形式都出现的字母。\n
\n\n

 

\n\n

提示：

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