I interviewed at Deloitte (Athens, Athens, Attica) in Mar 2026
Interview
3 small excercises LeetCode Style: //DELOITTE INTERVIEW QUESTION 2
//Split substring so no letter occurs more than once in each substring
//Return the min num of substrings into which the string has to be split
/*
1.Must always be true:no letter occurs more than once in each substring
2.Event forcing a boundary: Appearance of a letter more than once in a substring (a.k.a. duplicate detected)
3.Data Structure that tracks the constraint : Set
*/
public static int minNumUniqueSubStr(String s )
{
Set uniques = new HashSet<>();
int substringCount = 0;
for (char c: s.toCharArray())
{
if (uniques.contains(c))
{
substringCount++;
uniques.clear();// reset substring
}
uniques.add(c);
}
/*
When a duplicate is detected, we start a new substring and clear the set. At that moment, the current character is the first character of the new substring.
If we used else, we wouldn’t add the duplicate character to the new substring, which is wrong.*/
return substringCount;
}
Interview questions [1]
Question 1
//DELOITTE INTERVIEW QUESTION 2
//Split substring so no letter occurs more than once in each substring
//Return the min num of substrings into which the string has to be split
/*
1.Must always be true:no letter occurs more than once in each substring
2.Event forcing a boundary: Appearance of a letter more than once in a substring (a.k.a. duplicate detected)
3.Data Structure that tracks the constraint : Set
*/
HR phone call, then onsite test contains a few basic SQL queries and easy-medium leet code problems. To prep the best way make sure to rehearse your SQL queries writing
I applied through an employee referral. The process took 1+ week. I interviewed at Deloitte (Berlin) in Feb 2023
Interview
The Interviews got place in Greece and remotely. I had to do 3 interviews and an 1 hour test with 3 different problems in Java( I selected the specific language) , the first one was a call Interview where the half call was in Greek and the other half in English. They asked me some general questions and some technical skills that I have and which language I prefer to the coding test. The coding test was 1 hour or 90 mins and it had 3 problems. It was perfect for someone who had enough knowledges in programming as a Junior. Not too difficult and also not too easy. In the second interview we discussed more in depth things about me, like my education, my skills, what are my preferences, my experiences etc. We did a video call and in the end we discussed which programming language I would like to get interview for which where Java, JavaScript or Python and which team I would like to join (based of course the programming language that I selected). After deciding the team, the last interview was the technical one. Because the team that I selected had to do with databases the last interview I had to design a database and explain every step I do and why, and also we discussed my codes in the coding test that I did after the 1st interview and how I could improve it even more.