These algorithms were sought long before the concept of NP-completeness was even defined (Karp's 21 NP-complete problems, among the first found, were all well-known existing problems at the time they were shown to be NP-complete).
Acești algoritmi au fost căutați cu mult timp înainte de definirea conceptului de NP-completitudine (Cele 21 de probleme NP-complete ale lui Karp, printre primele găsite, erau toate problemele bine-cunoscute existente deja la momentul la care s-au dovedit a fi NP-complete).