Huffman Codes: mienzaniso kushanda

Panguva iyoyo, vanhu vashoma vanofunga pamusoro chokwadi, sei faira compression. Tichienzanisa rapfuura kushandiswa pauzima kombiyuta yava nyore zvikuru. Uye anenge munhu wose kushanda pamwe faira maitiro anoshandisa mafaira. Asi vanhu vashoma kufunga sei vanoshanda uye nei faira compression. Wokutanga chaizvo shanduro iyi vaiva Huffman Codes, uye vari kushandiswa nenzira dzakasiyana-siyana nevanhu archivers nhasi. vanozvishandisa vakawanda havatombobvumi kufunga sei nyore faira compression anotora nzvimbo uye riri kushanda zano. Munyaya ino tikatarisa kuti compression ndiko nuances rubatsiro nokukurumidza uye nyore chirongwa yeEncoding, uyewo kuona chii nheyo muti Coding.

History algorithm

The algorithm pamusoro vakarongeka Coding zvigadzirwa mashoko okutanga chaizvo rava bumbiro Huffman zvinganaka kare pezana remakore rechimakumi maviri, kureva muna 1952. Ndiye panguva iri nechepasi chedziviriro ruzhinji mapurogiramu vakasikwa kuti dzvinya ruzivo. Panguva iyoyo, imwe yenzvimbo dzine mukurumbira zvinyorwa vachishandisa bumbiro iri vari yamabhuku ZIP, ARJ, RAR nevamwe vazhinji. Uyewo, Huffman algorithm inoshandiswa tsonyera jpeg-mifananidzo uye zvimwe kwakajeka zvinhu. Eya, faxes zvose vari kushandisa Coding ano, yakaitwa muna 1952. Pasinei chokwadi kuti kubvira pakusikwa bumbiro akatora nguva yakareba kudai nhasi rinoshandiswa nenzira dzakasiyana-siyana membranes itsva uye midziyo akwegura uye ano marudzi.

The musimboti nyatsoshanda Coding

Hwaro Huffman algorithm rinosanganisira zano unokubvumira kutsiva kupfuura dzechokwadi, kazhinji yokuvamba zviratidzo coded binary hurongwa. Uye vaya vari ishoma, kutsiviwa yakareba Codes. Kupindana refu Huffman Codes kunoitika chete pashure hurongwa inoshandisa zvose shoma tsika. Nzira iyi inobvumira kuti kurerutsa urefu bumbiro rimwe chiratidzo shoko yepakutanga yose. The inokosha ndechokuti pakutanga ari Coding ndingangokuvara panowanikwa tsamba dzinofanira nechakare. Zviri kwavari achava akagadzirira uye yokupedzisira shoko. Pachishandiswa mashoko aya, yakatakura kunze kuvakwa Huffman yechiratidzo muti, pahwaro iyo ichaitwa tsamba yeEncoding kwacho arşive.

Huffman code, muenzaniso

Kuenzanisira algorithm, funga mumwe graphical musiyano pakati kuvakwa bumbiro muti. Kushandisa nzira iyi kuti tibudirire, zvakakodzera kujekesa tsanangudzo zvimwe tsika zvakakodzera pfungwa kwacho. The yakatarwa pakati muzvizhinji pakati nodes uye arcs, izvo rinotungamirirwa kubva raiva pedyo nebundu kuti raiva pedyo nebundu, inonzi girafu. Muti pachahwo girafu rine mamwe chaiwo zvivako:

• mumwe raiva pedyo nebundu zvingasanganisira hapana kupfuura rimwe arcs;
• mumwe nodes kunge pamudzi muti, kureva, hazvifaniri kuva chikamu chinhu chakakombama zvachose;
• kana hunde vanotanga kutamira achitevedza arcs, muitiro vanofanira kubvumira kuti zvakakwana chero nodes.

Panewo yakadaro chinhu, chikamu Huffman Codes nyoro womuti. Zviri raiva pedyo nebundu iyo varege kuenda chero chinhu chakakombama. Kana nodes vaviri zvakabatana nechimwe chinhu chakakombama, mumwe wavo ndiye mubereki mumwe mwana, zvichienderana iyo raiva pedyo nebundu iri chinhu chakakombama unodzima, uye chii chinobatanidzwa. Kana nodes maviri zvakafanana mubereki raiva pedyo nebundu, dzinonzi hanzvadzi nzvimbo. Kana, ari mashizha, anosiya kubva nodes ose arcs akawanda, zvino inonzi binary muti. Just saka ndiye Huffman muti. The peculiarity kuvakwa vezvikwata ndechokuti kurema mubereki mumwe akaenzana Verengai Zviidzo zvose nevana vahwo nodes.

An algorithm yokuvakwa muti Huffman

Kuvakwa Huffman code mazano kubva earufabheti. Vanowanika Nyora nzvimbo kuti vakasununguka mune ramangwana Mubumbiro muti. Kurema rimwe raiva pedyo nebundu iri pamazita vanofanira kuva kufanana ndingangokuvara panowanikwa tsamba namagwatidziro zvakafanana raiva pedyo nebundu iri. Panyaya iyi, uyo anoyera mudukusa anosarudzwa kubva pakati wandei akasununguka nzvimbo omuti ramangwana. Panyaya iyi, kana shoma prices vari kuchengetwa nzvimbo dzakawanda, unogona vakasununguka kusarudza chero yezvinoita. Kwozouya pakusikwa mubereki raiva pedyo nebundu, izvo anofanira kuongorora sekuda Verengai Zviidzo peya nodes. Pashure paizvozvo, vabereki kutumira zvawanyora vakasununguka zvimbudzi, uye vana vanobviswa. In chinhu chakakombama ichi akakodzera zviratidzo, vaya uye zeros. Izvi inodzokororwa zvakawanda vaifanira kuchengeta chete chete raiva pedyo nebundu. Zvadaro nyora kunze binary digits kubva kumusoro kusvikira pasi.

Kuvandudza kunyatsoshanda kuti compression

Kuti vawedzere compression kunyatsoshanda, zvakakodzera munguva muti chivakwa remitemo kushandisa zvose mashoko pamusoro ndingangokuvara panowanikwa tsamba neimwe faira, kuda muti, uye kubvumira kuti vakapararira pamusoro vakawanda rwezuva magwaro. Kana pre-famba kuburikidza faira ichi, unogona pakarepo ngaaverenge nhamba kuti kazhinji pane tsamba yacho pasi compression.

Kumhanyisa of compression kwacho

Kuti rikurumidze algorithm, tsanangudzo tsamba zvinofanira kuitwa kwete chibvumirano ndingangokuvara panowanikwa imwe tsamba, uye kakawanda parinowanika. With algorithm ichi kunova nyore, uye kushanda navo zvikuru nokukurumidza. uyewo haambotauri kushanda ne zvinoyangarara-pfungwa nokupesana. Uyezve, kushanda nzira iyi, iyo simba Huffman code, kana panzvimbo algorithm pachayo haina pasi chero kuchinja. Izvi kunyanya nokuti chokuti fungidziro vari Proportional kuti kakawanda zvakananga. Zvinokosha kuteerera chokwadi kuti kwokupedzisira kurema faira, kana anonzi mudzi raiva pedyo nebundu akaenzana kuwanda pazvinhu zviri chinhu kubatwa.

mhedziso

Huffman Codes - nyore uye-refu yakasimbiswa algorithm, iro richiri kushandiswa nevakawanda yaizivikanwa zvirongwa uye makambani. Its nyore uye zvakajeka anogona kuzadzisa vanobudirira migumisiro tsonyera mafaira chero bhuku uye kuderedza nzvimbo iri dhisiki chekuchengeta. Nemamwe mashoko, Huffman algorithm - yagara kuongororwa uye basa dhayagiramu iro yokukurumidzira haisi kuderedzwa nhasi. Uye vachikwanisa kuderedza ukuru mafaira, uchatamisa navo pamusoro nomumbure kana nevamwe kunoreva zviri zvikuru nyore, kutsanya uye yakakodzera. Kushanda pamwe algorithm, unogona tsonyera chero mashoko zvachose pasina kukuvadza wayo marongerwo uye quality, asi pamwe kunonyanyisa zvazviri kuderedza uremu faira. Mune mamwe manzwi, Coding of Huffman bumbiro yave uye anoramba nzira zvikuru nevanhu uye akakodzera kuti compressing faira saizi.