{ "data": { "question": { "questionId": "1448", "questionFrontendId": "1323", "categoryTitle": "Algorithms", "boundTopicId": 74728, "title": "Maximum 69 Number", "titleSlug": "maximum-69-number", "content": "

You are given a positive integer num consisting only of digits 6 and 9.

\n\n

Return the maximum number you can get by changing at most one digit (6 becomes 9, and 9 becomes 6).

\n\n

 

\n

Example 1:

\n\n
\nInput: num = 9669\nOutput: 9969\nExplanation: \nChanging the first digit results in 6669.\nChanging the second digit results in 9969.\nChanging the third digit results in 9699.\nChanging the fourth digit results in 9666.\nThe maximum number is 9969.\n
\n\n

Example 2:

\n\n
\nInput: num = 9996\nOutput: 9999\nExplanation: Changing the last digit 6 to 9 results in the maximum number.\n
\n\n

Example 3:

\n\n
\nInput: num = 9999\nOutput: 9999\nExplanation: It is better not to apply any change.\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "6 和 9 组成的最大数字", "translatedContent": "

给你一个仅由数字 6 和 9 组成的正整数 num。

\n\n

你最多只能翻转一位数字，将 6 变成 9，或者把 9 变成 6 。

\n\n

请返回你可以得到的最大数字。

\n\n

 

\n\n

示例 1：

\n\n
输入：num = 9669\n输出：9969\n解释：\n改变第一位数字可以得到 6669 。\n改变第二位数字可以得到 9969 。\n改变第三位数字可以得到 9699 。\n改变第四位数字可以得到 9666 。\n其中最大的数字是 9969 。\n
\n\n

示例 2：

\n\n
输入：num = 9996\n输出：9999\n解释：将最后一位从 6 变到 9，其结果 9999 是最大的数。
\n\n

示例 3：

\n\n
输入：num = 9999\n输出：9999\n解释：无需改变就已经是最大的数字了。
\n\n

 

\n\n

提示：

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