# Solving Leetcode Interviews in Seconds with AI: Largest 3-Same-Digit Number in String


	# Introduction
	In this blog post, we will explore how to solve the LeetCode problem "2264" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like [Chatmagic](https://www.chatmagic.app), 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 string num representing a large integer. An integer is good if it meets the following conditions:  It is a substring of num with length 3. It consists of only one unique digit.  Return the maximum good integer as a string or an empty string "" if no such integer exists. Note:  A substring is a contiguous sequence of characters within a string. There may be leading zeroes in num or a good integer.    Example 1:  Input: num = "6777133339" Output: "777" Explanation: There are two distinct good integers: "777" and "333". "777" is the largest, so we return "777".  Example 2:  Input: num = "2300019" Output: "000" Explanation: "000" is the only good integer.  Example 3:  Input: num = "42352338" Output: "" Explanation: No substring of length 3 consists of only one unique digit. Therefore, there are no good integers.    Constraints:  3 <= num.length <= 1000 num only consists of digits.  

	# Explanation
	Here's the breakdown of the solution:

*   **Iterate through substrings of length 3:** Check each substring of length 3 within the input string.
*   **Check for uniqueness:** For each substring, verify if all characters are the same.
*   **Track the maximum:** If a substring consists of the same digit, compare it with the current maximum good integer found so far, and update if necessary.

*   **Time Complexity:** O(n), where n is the length of the input string.
*   **Space Complexity:** O(1)

	
	# Code
	```python
	def largestGoodInteger(num: str) -> str:
    """
    Finds the largest "good" integer (substring of length 3 with same digits) within a given string.

    Args:
        num: The input string representing a large integer.

    Returns:
        The largest good integer as a string, or an empty string if none exists.
    """
    max_good_integer = ""
    for i in range(len(num) - 2):
        substring = num[i:i + 3]
        if substring[0] == substring[1] == substring[2]:
            if max_good_integer == "" or substring > max_good_integer:
                max_good_integer = substring
    return max_good_integer
	```