Backend Developer Interview Questions

9,192 backend developer interview questions shared by candidates

Given that you need to call for an external API and it costs X amount of money for each call, how could you waste the minimum amount of money and keep the values up to date? Obs. the values are reliable enough to be kept for 1min. And it has 2% failure rate overall.
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Backend Software Developer

Interviewed at Wise

3.6
May 2, 2022

Given that you need to call for an external API and it costs X amount of money for each call, how could you waste the minimum amount of money and keep the values up to date? Obs. the values are reliable enough to be kept for 1min. And it has 2% failure rate overall.

There were two coding questions and I was given a blank paper. Q1: find digit sum of all the questions till n. eg if n = 12, res = 51 (1+2+...+9 + (1+0) + (1+1) + (1+2)) Q1 was easy and I was able to code it. Q2 was tough here is the question http://stackoverflow.com/questions/11253027/algorithm-to-find-the-total-number-of-connected-sets-in-a-matrix I solved the problem, but was not able to code it properly as it was a long program and I had only paper. I thought i will explain the code later to the interviewer. I got rejected came back and coded both questions at home with same logic. Still dont know why I got rejected.
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Backend Developer

Interviewed at OYO

3.3
Aug 27, 2016

There were two coding questions and I was given a blank paper. Q1: find digit sum of all the questions till n. eg if n = 12, res = 51 (1+2+...+9 + (1+0) + (1+1) + (1+2)) Q1 was easy and I was able to code it. Q2 was tough here is the question http://stackoverflow.com/questions/11253027/algorithm-to-find-the-total-number-of-connected-sets-in-a-matrix I solved the problem, but was not able to code it properly as it was a long program and I had only paper. I thought i will explain the code later to the interviewer. I got rejected came back and coded both questions at home with same logic. Still dont know why I got rejected.

The question is about calculating the n-th fibonacci (F(n)) where n is an integer. Additionally, the interviewer asked you to optimize it as best as you could. The time complexity and space complexity are also asked. https://leetcode.com/problems/fibonacci-number/
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Associate Software Engineer - Backend

Interviewed at Agoda

3.9
Apr 29, 2022

The question is about calculating the n-th fibonacci (F(n)) where n is an integer. Additionally, the interviewer asked you to optimize it as best as you could. The time complexity and space complexity are also asked. https://leetcode.com/problems/fibonacci-number/

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