Laravel Collectionの計算量を調べてみた

Transcript

1. Laravel CollectionͷܭࢉྔΛௐ΂ͯΈͨ
   1)1ษڧձ
    *OOPWBUPS
   +BQBO
   *OD ෋ॴ
   ྄ &OHJOFFS

2. ܭࢉྔʹ͍͓ͭͯ͞Β͍ ຊ೔͸࣌ؒతܭࢉྔΛѻ͍·͢

3. ྫ͑͹ϨϏϡʔ͍ͯ͠Δ࣌

4. ʮ͜ͷॲཧ஗ͦ͏ʯ ͜Εͩͱ෼͔Γʹ͍͘ɻ ॲཧͷ࣌ؒత଎౓Λڞ௨஌ࣝͰ఻͍͑ͨ

5. ӳޠͩͱ Time Complexity ࣌ؒෳࡶੑ ϓϩάϥϜͷॲཧʹ ͲΕ͘Β͍͕͔͔࣌ؒΔ͔Λ ਺ֶతʹѻ͏

6. Oه๏ O(1) O(log n) O(n) O(n * log n) O(n^2)

   ϓϩάϥϜͷ࣌ؒతܭࢉྔΛද͢

7. Oه๏ σʔλྔ͕૿Ճͨ͠৔߹ͷ ॲཧ࣌ؒͷ૿Ճ܏޲͕෼͔Δ

8. [άϥϑҾ༻] ։ൃ৽ଔʹ๋͙ɺجຊͷΞϧΰϦζϜͱܭࢉྔ http://www.techscore.com/blog/2016/08/08/։ൃ৽ଔʹ๋͙ɺجຊͷΞϧΰϦζϜͱܭࢉྔ/ σʔλྔͱܭࢉྔ

9. ܭࢉྔͱΞϧΰϦζϜ ΞϧΰϦζϜ ܭࢉྔ όϒϧιʔτ 0 O? Ϛʔδιʔτ 0 O
   MPH
   O όΠφϦαʔν

   0 MPH
   O ΞϧΰϦζϜʹΑͬͯܭࢉྔ͕ҟͳΔ

10. ͞Βʹৄ͘͠஌Γ͍ͨਓ ਺ֶΨʔϧ4 ཚ୒ΞϧΰϦζϜ 2ষͱ6ষΛಡΉ΂͠

11. ຊ୊ʹ໭Δ

12. Laravel Collection֤ϝιουͷܭࢉྔ ΋͏ͪΐͬͱ͖Ε͍ʹ͠·͢…

13. ࡶʹ·ͱΊΔͱ • ΄ͱΜͲ O(n) • O(1) ͕9ݸ • O(n^2) Ҏ্͕8ݸ

14. ཁ஫ҙϝιου • collapse O(n^2) • crossJoin O(n^3) • diff O(n^t)

    • diffAssoc O(n^t) • flatMap O(n^2) • flatten O(n^2) • groupBy O(n^2) • intersect O(n^2)

15. ࣮ଌͯ͠Έͨ

16. where - O(n)       

       ॲཧ࣌ؒ(ඵ) σʔλ݅਺

17. count - O(1)       

       ॲཧ࣌ؒ(ඵ) σʔλ݅਺

18. collapse - O(n^2)       

        ॲཧ࣌ؒ(ඵ) σʔλ݅਺

19. crossJoin - O(n^3)       

       ॲཧ࣌ؒ(ඵ) σʔλ݅਺

20. diff - O(n^t)       

       ॲཧ࣌ؒ(ඵ) σʔλ݅਺ t͸field਺ʹґଘ͢Δ

21. ܭࢉྔ͕෼͔ͬͨͱͯ͠ Կ͔ྑ͍͜ͱ͋Δͷ͔ʁ

22. ஌Βͳ͍ͱѱ͍͜ͱ͕ى͖Δ

23. ࣮ࡍʹ͔͋ͬͨ΋͠Εͳ͍ ܭࢉྔ͕໰୊ʹͳͬͨίʔυྫ ※࣮࿩Λݩʹͨ͠ϑΟΫγϣϯͰ͢

24. શ݅औಘ ϖʔδϯάͷͨΊʹ શ݅ϧʔϓͰճ͢ ྫ1

25. શ݅औಘ ϖʔδϯάͷͨΊʹ શ݅ϧʔϓͰճ͢ ϖʔδͷޙ൒ʹߦ͚͹ߦ͘΄Ͳ ϧʔϓ͕ճͬͯ஗͘ͳΔ O(n) ྫ1

26. ߹Θٕͤ O(n^2) O(n)ΛೖΕࢠʹ͢Ε͹ύϫʔΞοϓ ྫ2 ୈ1ϧʔϓͰશ݅ճ͢ O(n) ୈ2ϧʔϓ΋શ݅ճ͢ O(n)

27. ୈҰҾ਺͸࠷େͰ਺ඦ݅ఔ౓͕ͩͬͨ ୈೋҾ਺ͷσʔλ਺͕੒௕͍ͯͬͯ͠… ྫ2 ୈ1ϧʔϓͰશ݅ճ͢ O(n) ୈ2ϧʔϓ΋શ݅ճ͢ O(n)

28. ྫ2ͷΞϧΰϦζϜΛ࡞ͬͯ ࣮ଌͯ͠ΈΔ

29. σʔλྔʹΑΔੑೳͷྼԽ         

          ॲཧ࣌ؒ(ඵ) σʔλ݅਺ (ୈ1,2 Ҿ਺ಉ͡)

30. ͪΌΜͱO(n^2)ͷ άϥϑʹͳͬͨ

31. ࣄલʹݕ஌Ͱ͖ͳ͍͔ʁ

32. ࣮͸ྫ̍ɾ̎ͷίʔυ͸ ୯ମςετ -> ௨ա ड͚ೖΕςετ -> ௨ա ௨աͯ͠͠·͍ͬͯͨ…

33. ෛՙςετ ίʔυϨϏϡʔ ࣄલݕग़Մೳͳࡆ

34. ෛՙςετ σʔλྔ͕ലେʹͳΔ͜ͱ͕ Θ͔͍ͬͯΔϓϩμΫτ͸ߦ͍ͬͯΔɻ ௨ৗͷϓϩμΫτͩͱ ͋Μ·Γ΍ͬͯΔͷݟͨ͜ͱແ͍ɻ

35. ίʔυϨϏϡʔ ϨϏϡΞʔͷεΩϧ΍ܦݧʹґଘ ࣄલʹܭࢉྔʹ͍ͭͯ νʔϜ಺Ͱษڧձͱ͔ͯ͠Ε͹ ࢦఠˍमਖ਼͸؆୯ͩͱࢥ͏

36. ؂ࢹπʔϧͰɺॲཧ࣌ؒͷϝτϦΫεΛݟͯ ཧ٧ΊͰॲཧ࣌ؒͷ஗͍෦෼ΛಛఆͰ͖Ε͹ ·͋ɺٴୈ఺ͩͱࢥ͏ɻ ࠷ѱݟಀͯ͠΋

37. ͓·͚

38. ܭࢉྔ͕Ұ໨ྎવ

39. σʔλͷू·ΓΛѻ͏ϓϩάϥϜ͸ ܭࢉྔ͕໌ࣔ͞Ε͍ͯΔͱ͋Γ͕͍ͨ

40. ͓͠·͍