Hōtaka Hihiri, te mau parau tumu

Hei tīpako i te otinga tino pai, ka e mahi ana e ētahi wā te mahi hōtaka e hiahiatia ana ki te kōmaka nui o ngā raraunga e utaina ana te mahara o te rorohiko whaiaro. ngā taua tikanga, hei tauira, te tikanga hōtaka o "wehenga me te ture". I roto i tenei take whakarato te hātepe wehenga raruraru ki tūmahiroto motuhake iti. he hāngai anake i roto i te hunga wā i reira e tahi motuhake tūmahiroto iti tenei tikanga. Ki te karo i te raveraa i te ohipa faufaa ki te taupuhipuhi iti-mahi, whakamahi tikanga hōtaka hihiri whakaarohia American R.Bellmanom i te 50s.

Ko te tikanga

hōtaka hihiri ko ki te whakatau i te otinga tino pai te raruraru n-ahu, te faaiteraa i tona n wāhanga motuhake. Ia o ratou ko te iti-mahi ki te whakapai kanohi ki te kotahi tāupe.

Ka taea te whakaaro te painga matua o tenei huarahi e te ngā wāhi i roto i te raruraru arotautanga kotahi-ahu tūmahiroto hei utu o te raruraru n-ahu, me to tatou whāinga tuatahi kei te haere ki te "raro-ake".

He mea tika ki te tono hōtaka hihiri i roto i aua wā i reira kei te honohono te iti-mahi, arā faaite kōwae noa. E whakarato ana te hātepe te whakatau o ia o nga tūmahiroto kotahi, me ngā whakautu faaoraraa e ravehia i te i roto i te ripanga motuhake. hanga tenei taea reira kore ki te tātai i te whakahoki, ka tutaki ano ratou ki te taua iti-mahi.

mahi hōtaka hihiri solves te raruraru o arotautanga. I whakatakoto te kaituhi o tenei tikanga nā Bellman optimality parau tumu: mea katoa ko te āhua tuatahi o ia o nga kaupae me te otinga tautuhi i roto i tenei taahiraa, katoa o te whai ake ki te whiriwhiri i te tino pai i roto i te pā ana ki te āhua, e tango ana i te pūnaha i te mutunga o te taahiraa.

whakapiki i te tikanga te mahi o nga mahi faatiti'aifarohia e tikanga o rerekē, recursion ranei.

Hātepe mahi Building

Hātepe papatono hihiri tā te hanga o taua mahi e te mahi pera e wahia ki e rua, neke atu rānei tūmahiroto ki tona otinga tito o te otinga tino pai ki tūmahiroto katoa te, ngā reira. I tua atu, he mea e tika ana ki te tuhituhi i te pā ana hohokitanga, me te tātai i te uara tawhā tino arotau mō te mahi rite te katoa.

I te tahi taime, i runga i te taahiraa 3, ko te ki te tamau aau i te tahi mōhiohio whakamārama atu i runga i te ahunga whakamua o ia mahi. huaina ana tēnei ko te patu hoki.

tikanga Taupānga

tono hōtaka hihiri te ka i reira e rua ngā āhuatanga āhuatanga:

• tino pai mō tūmahiroto;
• aroaro i roto i te raruraru o subproblems inaki.

Whakaoti i te raruraru arotautanga i te hōtaka hihiri, Me tuatahi koe ki te whakaahua i te hanganga o te otinga. kua ki te kia tino pai ki te tito i te otinga e o te whakatau pai o ona tūmahiroto te mahi. I roto i tenei take, he mea tika ki te whakamahi i hōtaka hihiri.

Ko te taonga tuarua o te raruraru, faufaa i roto i tenei tikanga, - he maha iti o te iti-mahi. otinga Recursive o te raruraru mā te whakamahi i te taua inaki iti-raruraru, te maha o e tei runga i te rahi o te mōhiohio tuatahi. Kei te rongoa te whakahoki i roto i te tepu motuhake, whakaora te hōtaka wā mā te whakamahi i tenei raraunga.

Rawa whai hua ko te whakamahi o te hōtaka hihiri, ina te hiahiatia tino te mahi ki te hanga whakatau i roto i ngā wāhanga. Hei tauira, whakaaro he tauira ohie o te raruraru o te whakakapinga, me te hanga o te taputapu. Kia mea a i runga i te wheketere mīhini whakaitinga mo te hanga o potae i te wa taua hanga te tupare i roto i ngā puka e rua rerekē. I roto i te kaupapa e kore tetahi o nga puka, he mea e tika ana ki te wetewete i te mīhini. 'Oku mahinongofua e ētahi wā atu pai ki te whakakapi me te puka tuarua i roto i te tikanga ki te wetewete i te mīhini i roto i te take, a ka kia pakeke i roto i te wā i muri mai i tēnei puka. Rawa mai te reira māmā ki te whakakapi i rua āhua mahi i mua i te tīmata ratou ki kore. tikanga hōtaka hihiri whakatau te rautaki pai i roto i te mea o te whakakapinga o enei puka, tango ki pūkete nga āhuatanga katoa: nga hua o tonu momo o te faaohiparaa i, mate o downtime mīhini, te utu o potae mahue me te ake.