Without backreferences, it has a worst-case exponential blow up due to the DFA possibly needing to simulate that many simultaneous NFA states. Regex matching w

Without backreferences, it has a worst-case exponential blow up due to the DFA possibly needing to simulate that many simultaneous NFA states. Regex matching with backreferences is NP-hard. - https://perl.plover.com/NPC/NPC-3SAT.html https://perl.plover.com/NPC/NPC-3SAT.html - https://perl.plover.com/NPC/NPC-3COL.html https://perl.plover.com/NPC/NPC-3COL.html