{ "data": { "question": { "questionId": "41", "questionFrontendId": "41", "categoryTitle": "Algorithms", "boundTopicId": 1368, "title": "First Missing Positive", "titleSlug": "first-missing-positive", "content": "

Given an unsorted integer array nums, return the smallest missing positive integer.

\n\n

You must implement an algorithm that runs in O(n) time and uses constant extra space.

\n\n

 

\n

Example 1:

\n
Input: nums = [1,2,0]\nOutput: 3\n

Example 2:

\n
Input: nums = [3,4,-1,1]\nOutput: 2\n

Example 3:

\n
Input: nums = [7,8,9,11,12]\nOutput: 1\n
\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "缺失的第一个正数", "translatedContent": "

给你一个未排序的整数数组 nums ，请你找出其中没有出现的最小的正整数。

\n请你实现时间复杂度为 O(n) 并且只使用常数级别额外空间的解决方案。\n\n

 

\n\n

示例 1：

\n\n
\n输入：nums = [1,2,0]\n输出：3\n
\n\n

示例 2：

\n\n
\n输入：nums = [3,4,-1,1]\n输出：2\n
\n\n

示例 3：

\n\n
\n输入：nums = [7,8,9,11,12]\n输出：1\n
\n\n

 

\n\n

提示：

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