Palantir Technologies Forward Engineer interview questions

First of all,I was contacted by a head hunter that kept telling me that I'm the right person for the job blah , blah ,blah. That person called me at least 50 times in a three months span. He did tell me to sharpen up on Algorithms and I did as much as I could, investing more time on those subjects are not the smartest decision as most companies (at least in my country) don't care. After that I had 3 phone interviews, made pretty well in the first two. The first one was with the HR lady, she was really sweet and nice. I think I passed this, then I got the second one and again, it was with a nice gentleman, it wasn't great, but he gave me a hint that I passed, he told me that I did fine at the end of the phone call. This interview, I had to write some code regarding Hashtable and I was claim. In the final interview, I didn't do well, at first he asked me mix questions regarding Java and I did pretty well, then he start moving about algorithms and stuff that you may use it once in your life time unless you developing the Java Virtual Machine itself. he asked me how to get the 3 numbers that sums to Zero within an array. I think I was not in my best mode, I just gave very wrong answer. What I didn't like about this experience that you need to do perfect all the time, and if you slip once you are out. The head-hunter will promise you stuff but he will not stand with you. I really wasted 4 months of my life for this job, I would recommend people to try to make start-up and take chance in there rather than to join un-profitoable demanding start-up like Palantir.