First Missing Positive
Examples
Example 1:
Input: nums = [1,2,0]
Output: 3
Explanation:
Example 2:
Input: nums = [3,4,-1,1]
Output: 2
Example 3:
Input: nums = [7,8,9,11,12]
Output: 1
Example 1:
Input: nums = [1,2,0]
Output: 3
Explanation:
Example 2:
Input: nums = [3,4,-1,1]
Output: 2
Example 3:
Input: nums = [7,8,9,11,12]
Output: 1
Given an unsorted integer array nums, return the smallest positive integer that does not appear in nums.
Your solution must run in O(n) time and use O(1) extra space.
The values 1 and 2 are present, so the smallest missing positive is 3.
1 <= nums.length <= 10^5-2^31 <= nums[i] <= 2^31 - 1