Package g0001_0100.s0041_first_missing_positive

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    41 - First Missing Positive.

    Hard

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

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

    Example 1:

    Input: nums = 1,2,0

    Output: 3

    Explanation: The numbers in the range 1,2 are all in the array.

    Example 2:

    Input: nums = 3,4,-1,1

    Output: 2

    Explanation: 1 is in the array but 2 is missing.

    Example 3:

    Input: nums = 7,8,9,11,12

    Output: 1

    Explanation: The smallest positive integer 1 is missing.

    Constraints:

    • <code>1 <= nums.length <= 10<sup>5</sup></code>

    • <code>-2<sup>31</sup><= numsi<= 2<sup>31</sup> - 1</code>

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer firstMissingPositive(IntArray nums)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait