Pergunta de entrevista da empresa Goldman Sachs

Round-2 First, interviewer asked me how good I am in different programming languages, especially in Java. I frankly said that I use python generally since I have to code in that for my academic assignments, but used java in summer, and I am good with OOPS in it. With him seeming that I was good at Java, he proceeded to go with that language and gave me the "first non-duplicate character in the string question". Since I luckily just used dictionary, I proceeded to go with that approach. First, i explained to him my intuitive though approach of storing the count values of char as they occur inside the string, in a hashmap, and then serially check in the hashmap if any key value has 1, and as soon as we get that key char, we return it. Interviewer approved to that approach and asked me to proceed to code it. Now here came the twist. I was actually not ready with Java! I even struggled to initialize hashmap of java.utils. Luckily, Interviewer was chill and I seek his help, but ultimately, I asked if I can switch to python (the point after which i felt really embarassed and a bit disappinted and underconfident about myself). He agreed to it, and I quickly coded my approach in python in 3-4 minutes and passed all the given test-cases. He then asked if I can think of more test-cases to check for code's correctness, especially the edge cases. I tried making 2-3 more, and he was kind of happy, but I missed the case of passing an empty string, which he explained that i should have done it. He was overall satisfied with me and we proceeded with system design part. he asked me about different components of any software system we would design, and then we discussed the same explicitly on a heart-rate monitoring machine. We had kinda long discussion, and I actually didn't had knowledge about design patterns or architecture, but was able to explain different possible requirements and solutions and the ways of designing the same. He liked my thought process and even explained about where I could have improved. He said we had 10 min extra discussion, so he was in a hurry, but seemed overall satisfied. Got selected finally.