Interviewing for big tech I always a very scary and ambitious situation. Recently I interviewed for a summer intern in Twilio and here's how it went down.

A few pointers before we start:

It was an on-campus opportunity 🏫
Yes, I got selected 🎉
The CTC for full-time was 43.4LPA (16LPA in hand) 💰
My stipend is 1.22LPA (84k in hand) 💰

Rounds

1. Coding round (90mins)

It was one of the best coding round I ever gave, for a change the problems weren't just random DSA problem but were actually based real world problem and were framed like a story in the terms of a problem faced by Twilio.

The first question was pretty simple, I don't exactly remember but it was something like

Given an array of files, having to data points

file URL

file size in bytes

We have to return files in categories of KB, MB, GB

input : [['link', 1234], ...]

The second question was a string manipulation question

Given a string use some given conditions to tell if it's telephone, WeChat, whatsApp or Invalid

WhatsApp = 'wta: 322424'

telephone = 'tel:2342423424'

weChat = 'wec:ireaf_343'

With a few more conditions for each

The second question ended up taking some time, but I still managed ti do both of them In 29mins which was pretty good.

2. Tech + HR interview

This round was a STAR + project discussion + CS Core interview. In my case the CS core question involved a Computer Networking question :

When we hit a domain in the browser what happens next ? Ans: A get request is sent to a DNS server, which gives us the IP associated with the domain and then we are routed through servers and finally receive a response

My answer was a little vague as I didn't know the complete answer but did know the basic so didn't want to be quiet or not answer

Other than that we discussed some of my projects, and my experience at my older workplace.

3. Coding interview

# In the pre-pandemic world (or when we get back in the office), we find it very challenging to find meeting rooms in 
# our Twilio offices and we want to solve that problem. We have the data of bookings for each conference room. For the sake of 
# this problem, we can assume that each meeting is one hour long. Each interval is one hour long. e.g. A session 2-10 consists
#  of 8 meetings of one hour each. (2,3), (3,4) ........ (9,10)

# Given this data (a set of booking timings across meeting rooms), find out the busiest hours of the day i.e when most the rooms are engaged concurrently.

# sample data set:

# room 1: 2-10
# room 2: 3-15
# room 3: 4-9
# room 4: 8-14
# room 5: 7-13
# room 6: 5-10
# room 7: 11-15

_input = [
    [2,10],
    [3,15],
    [4,9],
    [8,14],
    [7,13],
    [5,10],
    [11,15]
]


# O(n*m)+O(n) n=number of rooms, m=largest room interval
# def solution(testCase):
#     hours = [0]*24
#     for item in testCase:
#         start = item[0]
#         end = item[1]
#         for i in range(start-1,end):
#             hours[i]+=1
#     busy = max(hours)
#     print(f"BUSIEST HOUR => {hours.index(busy)+1}")
#     # print(f"FINAL {hours}")
#     pass


# O(n*m) n=number of rooms, m=largest room interval
def solution(testCase):
    hours = [0]*24
    busy = -1
    index = -1
    for item in testCase:
        start = item[0]
        end = item[1]
        for i in range(start-1,end):
            hours[i]+=1
            if busy<hours[i]:
                busy=hours[i]
                index = i
                print(hours,busy,index)

    print(f"Solution => {index+1}")
    pass


solution(_input)

I was able to get the a solution upto O(n) but I don't the solution to that. But in this interview they were more interested in compatibility and conversation during pair programming I say this because a friend of mine was able to get the solution quicker than me but was very quiet and didn't communicate a lot and hence didn't get selected.