Introduction

In this blog post, we will explore how to solve the LeetCode problem "2996" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

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. In particular, the prefix consisting only of nums[0] is sequential. Return the smallest integer x missing from nums such that x is greater than or equal to the sum of the longest sequential prefix. Example 1: 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. Example 2: Input: nums = [3,4,5,1,12,14,13] Output: 15 Explanation: The longest sequential prefix of nums is [3,4,5] with a sum of 12. 12, 13, and 14 belong to the array while 15 does not. Therefore 15 is the smallest missing integer greater than or equal to the sum of the longest sequential prefix. Constraints: 1 <= nums.length <= 50 1 <= nums[i] <= 50

Explanation

Here's a breakdown of the solution:

• Identify Longest Sequential Prefix: Iterate through the array to determine the longest sequential prefix starting from the beginning.
• Calculate Prefix Sum: Compute the sum of the elements within this identified longest sequential prefix.

• Find Missing Integer: Starting from the calculated sum, incrementally check if each subsequent integer exists within the input array. Return the first integer that is not present in the array.

• Runtime Complexity: O(n), where n is the length of the input array nums.

• Storage Complexity: O(1) - constant extra space.

Code

    def solve():
    nums = [int(x) for x in input().split(",")]
    n = len(nums)

    longest_prefix_length = 1
    for i in range(1, n):
        if nums[i] == nums[i-1] + 1:
            longest_prefix_length += 1
        else:
            break

    prefix_sum = sum(nums[:longest_prefix_length])

    missing_integer = prefix_sum
    while missing_integer in nums:
        missing_integer += 1

    print(missing_integer)

# Example Usage (for testing purposes - remove when submitting)
# nums = [1,2,3,2,5]  # expected output: 6
# solve()

# nums = [3,4,5,1,12,14,13]  # expected output: 15
# solve()

# For submission, read input like this (assuming the nums array is read from stdin)
# if __name__ == "__main__":
#     solve()