"""
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.
"""


class Largest3SameDigitNumberInString:
    def largestGoodInteger(self, num: str) -> str:
        return max(num[i - 2: i + 1] if num[i] == num[i - 1] == num[i - 2] else "" for i in range(2, len(num)))
