Black hat Black hat A black hat hacker (or black-hat hacker) is a hacker who "violates computer security for little reason beyond maliciousness or for personal gain". The term's origin is often attributed to hacker culture theorist Richard Stallman (though he denies coining it) to contrast the exploitative hacker with the white hat hacker who hacks protectively by drawing attention to vulnerabilities in computer systems that require repair. The black hat/white hat terminology originates in the Western genre of popular American culture, in which black and white hats denote villainous and heroic cowboys respectively. Black hat hackers are the stereotypical illegal hacking
Prefix sum are calculated in the first pass on each processing unit; the prefix sum of these partial sums is then calculated and broadcast back to the processing units for a second pass using the now known prefix as the initial value. Asymptotically this method takes approximately two read operations and one write operation per item. When a data set may be updated dynamically, it may be stored in a Fenwick tree data structure. This structure allows both the lookup of any individual prefix sum value and the modification of any array value in logarithmic time per operation.. However, an earlier 1982