Skip to content

2264. Largest 3-Same-Digit Number in String

Difficulty Topics

Description

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.

Solution

largest-3-same-digit-number-in-string.py
class Solution:
    def largestGoodInteger(self, num: str) -> str:
        res = ""

        for key, group in itertools.groupby(num):
            if len(list(group)) >= 3:
                res = max(res, key * 3)

        return res