Doogal Simpson

Quick Answer: Measuring execution time using wall-clock functions like Date.now() or System.currentTimeMillis() can yield negative durations if your server synchronizes its clock mid-operation. To measure elapsed code performance accurately, always use monotonic clock APIs like performance.now() in JavaScript or System.nanoTime() in Java, which strictly count forward from an arbitrary baseline.

TL;DR: CPython stores strings using PEP 393 (Flexible String Representation) rather than UTF-8. It selects a fixed width of 1, 2, or 4 bytes per character based on the widest character present. If an ASCII string contains just one 4-byte emoji, Python instantly upgrades every single character in that string to 4 bytes, quadrupling its memory footprint. Imagine loading a massive log file into memory, doing basic parsing, and watching your server's RAM jump from 100 MB to 400 MB.

Quick Answer: Hashcash, created by Adam Back in 1997, introduced Proof of Work to combat email spam by requiring senders to solve a computationally asymmetric puzzle. By forcing senders to compute a hash with leading zero bits, it imposed a tiny delay on single emails while rendering mass spam computationally infeasible—a principle Satoshi Nakamoto later adapted for Bitcoin consensus.