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.


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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.


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Constraints:


	3 &lt;= num.length &lt;= 1000
	num only consists of digits.


class Solution:
    def largestGoodInteger(self, n: str) -> str:
        return max(n[i-2:i+1] if n[i] == n[i - 1] == n[i - 2] else "" for i in range(2, len(n)))
class Solution
{
    public String largestGoodInteger(String num)
    {
        String ans = "";
        for(int i = 2; i < num.length(); i++)
            if(num.charAt(i) == num.charAt(i-1) && num.charAt(i-1) == num.charAt(i-2))
                if(num.substring(i-2,i+1).compareTo(ans) > 0) // Check if the new one is larger
                    ans = num.substring(i-2,i+1);
        return ans;
    }
}
class Solution {
public:
    string largestGoodInteger(string num) {
        string ans = "";
        for(int i=1; i<num.size()-1; i++) {
            if(num[i-1] == num[i] && num[i] == num[i+1]) {
				string temp = {num[i-1], num[i], num[i+1]};
                ans = max(ans, temp);
            }
        }
        return ans;    
    }
};
var largestGoodInteger = function(num) {
    let maxGoodInt = '';
    for (let i = 0; i <= num.length - 3; i++) {
        if (num[i] === num[i+1] && num[i+1] === num[i+2]) {
            if (num[i] >= maxGoodInt) {
                maxGoodInt = num[i];
            }
        }
    }
    return maxGoodInt + maxGoodInt + maxGoodInt;
};
Largest 3-Same-Digit Number in String