Introduction

In this blog post, we will explore how to solve the LeetCode problem "217" 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

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Example 1: Input: nums = [1,2,3,1] Output: true Explanation: The element 1 occurs at the indices 0 and 3. Example 2: Input: nums = [1,2,3,4] Output: false Explanation: All elements are distinct. Example 3: Input: nums = [1,1,1,3,3,4,3,2,4,2] Output: true Constraints: 1 <= nums.length <= 105 -109 <= nums[i] <= 109

Explanation

• Hashing: Utilize a hash set (or dictionary) to efficiently check for the presence of each number in the input array.
  • Early Exit: Immediately return true if a duplicate is found during the iteration. This avoids unnecessary processing.

• Runtime Complexity: O(n), where n is the length of the input array.
• Storage Complexity: O(n) in the worst case, where n is the number of distinct elements in the array (occurs if all elements are unique).

Code

    def containsDuplicate(nums: list[int]) -> bool:
    """
    Given an integer array nums, return true if any value appears at least twice in the array,
    and return false if every element is distinct.
    """
    seen = set()
    for num in nums:
        if num in seen:
            return True
        seen.add(num)
    return False