Rizzle (SilverLabs) Interview Experience for SDE-2

Hi, I recently went through the interview process at Rizzle. On 20th May, a recruiter from Naukri.com reached out to me regarding SDE2 [Backend Engineer] position at Rizzle.

Timeline: The complete process took around 2 weeks.

HR asked for all my details and then scheduled the First round of interviews on the following day.

Round 1 ( F2F ):  The interviewer introduced herself and asked me to tell her about my current work and project. This went on for around 10 minutes then she jumped to questions. She was a Lead Engineer at Rizzle.

She first started with subjective questions.

1.  What are the specialties of NodeJS.
2. Difference between HTTP and HTTPS.
3. Difference between SQL and NoSQL.
4. What is Race Condition?
5. What are four criteria for Deadlock to happen?
6. What is LRU policy?

After these questions, she jumped to coding questions. She asked two coding questions.

• https://www.geeksforgeeks.org/find-first-repeating-element-array-integers/
  • At first I told her the brute force approach of using two nested loops [ O(n2)  TC ]
  • She asked me to optimize it. I then told her about the Hashing method with Linear time complexity using linear space. But she asked me to do it using constant space.
  • I then told her the approach of marking every element as negative. eg. for array element j we will make arr[j] as -arr[j], so in this way, if a number repeats (let’s say k) then arr[k] will be positive and thus we’ll get our first repeating number. This uses linear time and no space but It only works for positive numbers. She was happy with the solution.

C++

int findFirstRepeatingElement(int arr[],int n){
    for (int i = 0; i < n; ++i)
    {
        int j = abs(arr[i]);
        arr[j] = arr[j]*-1;
        if(arr[j]>=0) return arr[i];

    }
    return -1;
}

•  https://leetcode.com/problems/construct-k-palindrome-strings/
  • I had already solved this problem so I was able to come up with an efficient solution.

C++

bool kpalindrome(string s, int k){
    if(k>s.length()) return false;
    if(k==s.length()) return true;
    int count[26] = {0};

    for(char c : s){
        count[c-'a']++;
    }
    int oddCount = 0;
    for(int item : count){
        if(item%2!=0) oddCount++;
    }
    if(oddCount<=k) return true;
    return false;
}

After these questions, this round was completed and she asked me if I had any questions for her.

I got a call back from HR on the very next day, saying I have cleared my first round and they’ll be scheduling my second round.

Round 2 ( F2F ): One week later HR scheduled this round. The interviewer introduced himself and asked me to tell him about my current work and project. He quickly jumped to questions. He was a Director of Engineering at Rizzle.

Ths Round has Two coding Questions and One HLD question.

• First Question:  You have given a string, you have to reverse only the vowels in a string. I gave him a linear time approach and he was happy with that. He then shared a link to a leetcode question and asked me to solve it.
• Second Question: https://leetcode.com/problems/decode-string/
  I was able to come up with the stack-based approach. I explained to him the approach and wrote the code. He then asked me to run it. fortunately, all test cases passed.

These two questions took around 45 minutes. He then jumped to the Design question.

Third Question (HLD):

• He asked me to design a Job scheduler.
• There is a POST API through which we will be receiving a Job id and a timestamp. We need to push this job id to some queue at the given timestamp. 
• He asked me to do a High-Level Design of the system. He focussed mainly on scaling and how would I handle fault tolerance.

We had a very healthy conversation on this. It lasted for around 30 minutes. After which he seemed satisfied and said that That’s it from his side. He then asked if I had any questions.

RESULT: Two hours later I received a call from HR saying that I have cleared all my rounds and they’ll be rolling out my offer soon. 

VERDICT: Selected