GeeksForGeeks/2264. Largest 3-Same-Digit Number in String.cpp at main · chakrabortyrajarshi2005/GeeksForGeeks · GitHub

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Code
Testcase
Test Result
Test Result
2264. Largest 3-Same-Digit Number in String
Solved
Easy
Topics
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Hint
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 Solution {
    private List<String> sameDigitNumbers = List.of("999", "888", "777", "666", "555", "444", "333", "222", "111", "000");

    // Check whether the 'num' string contains the 'sameDigitNumber' string or not.
    private boolean contains(String sameDigitNumber, String num) {
        for (int index = 0; index <= num.length() - 3; ++index) {
            if (num.charAt(index) == sameDigitNumber.charAt(0) &&
                num.charAt(index + 1) == sameDigitNumber.charAt(1) &&
                num.charAt(index + 2) == sameDigitNumber.charAt(2)) {
                return true;
            }
        }
        return false;
    }

    public String largestGoodInteger(String num) {
        // Iterate on all 'sameDigitNumbers' and check if the string 'num' contains it.
        for (String sameDigitNumber : sameDigitNumbers) {
            if (contains(sameDigitNumber, num)) {
                // Return the current 'sameDigitNumbers'.
                return sameDigitNumber;
            }
        }
        // No 3 consecutive same digits are present in the string 'num'.
        return "";
    }
}