I'd say it depends on the firm. They could write and even implement algorithms, but they might also just spend most of their time monitoring and fine-tuning existing algorithms.
That sounds interesting. Its exactly the kind problem solving I enjoy. You also gave some good advice on what prerequsites are needed to work as a HFT trader. Is HFT the same as algorithmic trading? If not what are the differences?
Algorithmic trading can just mean trying to place orders with minimal slippage, e.g. if you were a bank that only places one order per day, that's definitely not HFT, but you might still want to get the best price for that order, which you won't if you just place it all in one go.
