Smallest Missing Integer Greater Than Sequential Prefix Sum — LeetCode 2996 Python Solution

EasyArrayHash TableSorting
Problem
#2996
Pattern
Sorting
Reading time
2 min

The problem

You are given a 0-indexed array of integers nums. A prefix nums[0..i] is sequential if, for all 1 <= j <= i, nums[j] = nums[j - 1] + 1.

Example

Input
nums = [1,2,3,2,5]
Output
6
Explanation
The longest sequential prefix of nums is [1,2,3] with a sum of 6. 6 is not in the array, therefore 6 is the smallest missing integer greater than or equal to the sum of the longest sequential prefix.

Python solution

Python
class Solution:
    def missingInteger(self, nums: List[int]) -> int:
        s, j = nums[0], 1
        while j < len(nums) and nums[j] == nums[j - 1] + 1:
            s += nums[j]
            j += 1
        vis = set(nums)
        for x in count(s):
            if x not in vis:
                return x

Complexity

MeasureComplexity
TimeO(n)
SpaceO(n), where n is the length of the array nums auxiliary

Pattern: Sorting

Spend O(n log n) once to buy an ordering that makes the rest of the problem trivial. LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum is filed here because LeetCode tags it Sorting, which is the vocabulary this hub collects.

The sorting guide has the Python template for the pattern and the 401 LeetCode problems that use it.

Related problems

Frequently asked questions

How hard is LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum?
LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum is rated Easy on LeetCode.
What is the time complexity of LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum?
The Python solution on this page runs in O(n).
What is the space complexity of LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum?
The Python solution on this page uses O(n), where n is the length of the array nums auxiliary space.
What topics does LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum cover?
LeetCode 2996. Smallest Missing Integer Greater Than Sequential Prefix Sum is tagged Array, Hash Table and Sorting on LeetCode.

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