I received a questionnaire from HR. After that, a Zoom interview was set up for the following week. It was a CoderPad interview and went well. I received positive feedback from the interviewer and was told to expect a call for the next round the following week. However, I heard nothing from HR for the next two weeks. Finally, I received a rejection stating they had selected another candidate. After a few weeks, I received another email from HR stating they had reopened the position and asked if I was still interested. I proceeded with them and received an onsite interview call. There were three rounds: two coding and one system design.

Simple String problem