
redos

seva seey incar (redos) kii ack niyamit abhivyakti
ack algorithmic jatilata hamla haye joe ack niyamit abhivyakti aur/yaa ack input pradaan karke seva seey incar kartaa haye jiska mulyankan karane mein lamba samay lagata haye. hamla iss tathya kaa fayda uthaata haye kii kaee niyamit abhivyakti karyanvayanon mein atee-raikhik sabse kharaab-sthiti jatilata hoti haye; kuchh rejex-input jode parr, liya gayaa samay input aakar key sambandh mein bahupad yaa teji seey badh sakata haye. iss prakaar ack hamlawar vishesh roop seey taiyar niyamit abhivyakti aur/yaa input pradaan karke ack karyakram koo paryaapt samay bitaane kaa kaaran bunn sakata haye. karyakram taba dheema hoe jaayega yaa anuttardaayi hoe jaayega.
varnan.
niyamit abhivyakti ("rejex") milan ack seemit-avastha swachaalit nirmaan dwara kiya jaa sakata haye. rejex koo aasaani seey gair-nirdhaarak swachaalit (aine. aff. aeye. aiss.) mein parivartit kiya jaa sakata haye, jisamen pratyek raajya aur input prateek key liye, kaee sambhaavit agali sthitiyaan hoe sakati hain. automaton key nirmaan key baad, kaee sambhaavanaaen maujood hainh
uparokt algorithm mein seey pahale dou samasyagrast hain. pahala samasyagrast haye kyonki ack nirdhaarak swachaalit sootra 1 avastha taka hoe sakata haye jahan sootra 2 gair-nirdhaarak swachaalit mein avasthaon kii sankhya haye; iss prakaar, aine. aff. aeye. seey dee. aff. aeye. mein roopaantaran mein ghaatiya samay lugg sakata haye. doosara samasyagrast haye kyonki ack gair-nirdhaarak swachaalit mein lambai sootra _ 3 key pathon kii ghaatiya sankhya hoe sakati haye, taaki lambai sootra _ 3 key input key madhyam seey chalane mein bhee ghaatiya samay lagega.
haalaanki, antim dou algorithm rogjanak vyavhaar kaa pradarshan naheen karate hain.
dhyaan dein kii gair-roga sambandhi niyamit abhivyaktiyon key liye, samasyagrast algorithm aamtaur parr tej hotey hain, aur vyavhaar mein, koee bhee unase oh (aim) samay mein ack rejex koo "sankalit" karane aur oh (aine) samay mein milan karane kii ummeed curr sakata haye; isake bajaay, ack nfa kaa anukaran aur dfa kii aalsi ganana mein oh (aim2aine) sabse kharaab-sthiti jatilata hoti haye. seva kaa rejex incar taba hotaa haye jaba yeye apekshaaen upayogkarta dwara pradaan kiye gaye rejex parr lagu kii jaati hain, aur upayogkarta dwara pradaan kii gaee durbhavanapurna niyamit abhivyaktiyaan rejex matcher kii sabse kharaab-sthiti jatilata koo trigger karati hain.
jabaki rejex algorithm koo ack kushal tareeke seey likhaa jaa sakata haye, astitva mein adhikansh rejex injan atirikt sanrachanaon key saath rejex bhaashaon kaa vistaar karate hain jinhen hamesha kushalata seey hull naheen kiya jaa sakata haye. iss tarah key vistaarit pattern anivarya roop seey adhikansh prograaming bhaashaon mein rejex key karyanvayan koo backtracking kaa upayog karane key liye majboor karate hain.
udaaharan.
ghaatiya backtracking.
sabse gambhir prakaar kii samasya niyamit abhivyakti milan key saath hoti haye, jahaan kuchh pattern mein ack runtime hotaa haye joe input string kii lambai mein ghaatiya hotaa haye. sootra _ 3 varnon key taaron key liye, runtime sootra _ 6 haye. yeh taba hotaa haye jaba ack niyamit abhivyakti mein teen guna hotey hainh
doosari sthiti koo dou udaharanon key saath sabse achchi tarah seey samajhaaya gayaa haih
inn donon udaharanon mein hamane string key anta seey mell khaane key liye coce _ 10 kaa upayog kiya, teesari shart koo santusht kiya, lekin isake liye ack anya charitra kaa upayog karna bhee sambhav haye. udaaharan key liye, cock _ 11 mein samaan samasyagrast sanrachana haye.
uparokt teenon niyamit abhivyaktiyaan ghaatiya runtime pradarshit karengi jaba form formula _ 7 key taaron parr lagu kii jaayengi. udaaharan key liye, yadi aap unhein backtracking abhivyakti injan parr cock _ 12 key khilaf milan karane kaa prayaas karate hain, tou ise puuraa honey mein kaafee lamba samay lagega, aur cock _ 14 seey pahale pratyek atirikt cock _ 5 key liye runtime lagbhag doguna hoe jaayega.
yeh bhee sambhav haye kii ghaatiya key bajaay bahupad samay sootra _ 8 kaa peechhe kii or jaanaa hoe. yeh lambe samay taka paryaapt nivesh key liye bhee samasyaon kaa kaaran bunn sakata haye, halanki iss samasya parr cumm dhyaan diyaa gayaa haye kyonki durbhavanapurna input koo mahatvapurna prabhaav daalane key liye bahut lamba honah chaahiye. iss tarah key pattern kaa ack udaaharan "cock _ 15" haye, jaba input "cock _ 5" kaa manmaane dhang seey lamba anukram hotaa haye.
online bhandaron mein kamjor rejex.
tathaakathit "burai" yaa kamjor rejex online niyamit abhivyakti bhandar mein paae gaye hain. dhyaan dein kii poorna rejex parr hamla karane key liye ack kamjor "upa" abhivyakti khojane key liye yeh paryaapt haih
yeye dou udaaharan input cock _ 12 key liye bhee atisamvedansheel hain.
hamale.
yadi rejex swayam upayogkarta input seey prabhaavit haye, jaise kii ack web seva joe grahakon koo khoj pattern pradaan karane kii anumati detee haye, tou ack hamlawar server key sansadhanon kaa upbhog karane key liye ack durbhavanapurna rejex kaa injection lagaa sakata haye. isaliye, adhikansh mamalon mein, server parr upayogkarta key manmaane dhang seey pattern nishpaadit karane kii sambhavana koo hataakar seva key niyamit abhivyakti incar seey bachaa jaa sakata haye. iss mamle mein, web anuprayog aur databases mukhya kamjor anuprayog hain. vaikalpik roop seey, ack durbhavanapurna prishth upayogkarta key web brouser koo latka sakata haye yaa ise manmaane dhang seey memori kaa upayog karane kaa kaaran bunn sakata haye.
haalaanki, yadi server-side parr pahale seey hii ack kamjor rejex maujood haye, tou ack hamlawar isake bajaay ack input pradaan karane mein saksham hoe sakata haye joe isake sabse kharaab vyavhaar koo trigger kartaa haye. iss mamle mein, ee-mell scanner aur ghuspaith kaa pataa lagaane vaali pranaaliyan bhee asurakshit hoe sakati hain. saubhagya seey, adhikansh mamalon mein, samasyagrast niyamit abhivyaktiyon koo "gair-dusht" pattern key roop mein phir seey likhaa jaa sakata haye. udaaharan key liye, cock _ 20 koo cock _ 21 mein phir seey likhaa jaa sakata haye.
web anuprayog key mamle mein, programmer client aur system key server paksh donon parr input koo maanya karane key liye ack hii niyamit abhivyakti kaa upayog curr sakata haye. ack hamlawar graahak code kaa nireekshan curr sakata haye, niyamit roop seey kharaab abhivyaktiyon kii talash curr sakata haye, aur ise latkaane key liye seedhe web server koo taiyar kiye gaye input bhej sakata haye.

