Citi Summer Analyst Technology interview questions

I had one tech interview with a recruiter from the team at citi bank. It involved checking if a string is a valid palindrome by using two pointers method, and another was about checking for duplicates in a string, which used a hashmap.

1 OA followed by 2 Online interviews with VPs. Scheduled the interview last minute (on the very next day), giving me 30 minutes to respond if I want to reschedule. Went along anyway despite having classes at that time. Emailed the recruiter twice to see if it was technical or just behavioral, completely ignored my email to this day. The interviewers were nice, but it seemed like they were in a rush probably doing multiple interviews in a day. Ultimately got rejected at the end after 2 weeks, I found out by checking the workday portal, they didn't even had the courtesy to send me an email to reject me after the interview.