R1. Matrix Multiplication and the Master Theorem

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  • Опубліковано 30 вер 2024

КОМЕНТАРІ • 48

  • @kimhammar
    @kimhammar 8 років тому +88

    Master Theorem 33:10

    • @klejdisevdari3916
      @klejdisevdari3916 3 роки тому

      This comment saved me so much time. Thanks

    • @gerardorigas6812
      @gerardorigas6812 3 роки тому

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    • @maverickpierce3090
      @maverickpierce3090 3 роки тому

      instablaster...

  • @halfEnlightenedOne
    @halfEnlightenedOne 3 роки тому +12

    02:16 Weighted Interval Scheduling
    22:40 Strassen algorithm
    33:16 Master Theorem

  • @ZhenyuWu-i5h
    @ZhenyuWu-i5h 3 роки тому +23

    Graduted from QingHua(top university in CN) as a bachelor, this guy is brilliant.

    • @AMANKUMAR-oh1zt
      @AMANKUMAR-oh1zt 3 роки тому +3

      Means he is a commie??

    • @jackzeinder1705
      @jackzeinder1705 2 роки тому +5

      @@AMANKUMAR-oh1zt do you guys still have toilet?

    • @AMANKUMAR-oh1zt
      @AMANKUMAR-oh1zt 2 роки тому +2

      @@jackzeinder1705 Aapke hote hue toilet ki kya zarurat hai? :-)

    • @jackzeinder1705
      @jackzeinder1705 2 роки тому

      @@AMANKUMAR-oh1zt kya tum log ab bhee gaay ke gobar se dhote ho ? :)

    • @lxu5148
      @lxu5148 2 роки тому

      @@AMANKUMAR-oh1zt Then he may be able to put you inside?

  • @hektor6766
    @hektor6766 5 років тому +10

    Recitation is where things happen.

  • @pkatmusic5800
    @pkatmusic5800 4 роки тому +6

    I think after viewing Professor Gilbert Strang's video lecture on matrix multiplication, you won't ever forget it. I mean it. 🙂🙂🙂

  • @woodsker
    @woodsker 8 років тому +22

    Strassen’s algorithm 22:30

    • @degerahmet
      @degerahmet 5 років тому +2

      dude you are the man !

  • @mytennisjourney4949
    @mytennisjourney4949 3 роки тому +3

    Thanks! I always have no feeling about master theorem, now I understand to prove process, it makes more sense for me. Another way to think about this, the recursion tree can prove the master theorem, so it can solve all concrete problem.

  • @sumitgupta1457
    @sumitgupta1457 7 років тому +6

    Great video on master theorem

  • @peasant12345
    @peasant12345 2 роки тому +1

    14:26 specifying wis(r1) needs log n comparisons in worst case. But the total complexity is still dominated by sorting part.

  • @Karim-nq1be
    @Karim-nq1be Рік тому +1

    I really enjoyed the way the instructor was explaining, thank you.

  • @williamkosasih6907
    @williamkosasih6907 5 років тому +3

    this guy's very good in teaching

  • @xinli6243
    @xinli6243 5 років тому +2

    the weighted interval scheduling. Why was the first alg n squared and second one just n? it takes constant time to computer R1?

    • @rewolfer
      @rewolfer 4 роки тому

      I also wondered about the cost of finding R1...

    • @safoorayousefi3814
      @safoorayousefi3814 4 роки тому +2

      I think Ling forgot to mention that cost. Having sorted the job array by start time, finding the next job whose start time is greater than the finish time of job_i can be done using binary search (O(logN)).

    • @WeirdAlSuperFan
      @WeirdAlSuperFan Рік тому

      Is finding the intervals in R the only reason the first algorithm is n^2? I feel like in both cases we're assuming R is constant time, but there's a different reason the unsorted algorithm is n^2, but I can't find an explanation anywhere on the internet or in textbooks

  • @bazingadmc720
    @bazingadmc720 2 роки тому +1

    关于weighted interval scheduling有个疑问,通过i1的end time去找R1(start time在i1 end time之后的interval)不就需要O(n)的时间吗,并且递归过程中每一步都有这个计算过程。

    • @peasant12345
      @peasant12345 2 роки тому

      binary search will consume log n. Still safe to get n log n.

  • @AndreyVarlamov
    @AndreyVarlamov 7 років тому +4

    Great vigeo. Thanks.

  • @qin6409
    @qin6409 2 роки тому +1

    mit有华人不容易,且尊重且珍惜

  • @mingyang8183
    @mingyang8183 5 років тому +3

    amazing teacher

  • @chilily901
    @chilily901 3 роки тому +1

    Thanks! Great professor, learned a lot today ^^~

  • @yiran432
    @yiran432 Рік тому

    So..... anyone can explain the philosophy of Strassen's method?🙂

    • @bhaskarkurapati1907
      @bhaskarkurapati1907 10 місяців тому

      What I understood that Strassen was trying to reduce "a" in Master Theorem formula from 8 to 7 so that first condition n ^ (log a with base b) would result in n^2.8074 instead of n^3. I remember reading the idea in "Introduction to Algorithms" book that multiplication/division are expensive computational operations than addition/subtraction. "a^2 - b^2" (which involves two multiplications and one subtraction) can be computed with "(a + b) * (a - b)" (which involves single multiplication). Strassen used similar strategy to reduce matrix multiplications from 8 to 7.

  • @amitsrivastava5690
    @amitsrivastava5690 3 роки тому

    37:00 a is branching factor and base case.

  • @tanushmahajan3359
    @tanushmahajan3359 3 роки тому

    22:34 Matrix Multiplication (Strassen)

  • @dunket777
    @dunket777 6 років тому

    video is not clear at 29:57 the values of M6 in first bracket are not clear

  • @zhanglei1032
    @zhanglei1032 5 років тому +1

    华人小哥?

    • @Victor-yn6jm
      @Victor-yn6jm 4 роки тому +2

      应该是中国人,清华毕业的

  • @gerdhickl4991
    @gerdhickl4991 Рік тому

    Test

  • @dr.rahulgupta7573
    @dr.rahulgupta7573 3 роки тому

    Nice presentation of the topics in a beautiful manner by an experienced teacher .Thanks .DrRahul Rohtak Haryana India

  • @RishabhKumar-sc8uz
    @RishabhKumar-sc8uz 6 років тому +1

    Bc video me dj mix Kra h

  • @mohamednofal5256
    @mohamednofal5256 5 років тому

    asians are good

  • @amornchotsingh3977
    @amornchotsingh3977 6 років тому

    Hello Everybody, I don't understand how this course works. There are lecture videos taught by the lecturers and also videos taught by students with prefix R1,R2,R3, etc. If I'm not wrong, are R1,R2 revision videos of official video 1 and 2? Or are they supplementary to the videos taught by the lecturer?

    • @mitocw
      @mitocw  6 років тому +11

      These supplementary videos are recitations. Recitations are a way for students to ask follow-up questions to anything that was confusing in lectures. For the full course materials, see the course on MIT OpenCourseWare at:ocw.mit.edu/6-046JS15. Best wishes on your studies!

  • @pinusong
    @pinusong 11 місяців тому

    看到了华人在 MIT讲课,厉害了,加油,大家都是优秀的人

  • @yuanchun9124
    @yuanchun9124 7 років тому

    [?Grady?] --> greedy =、= 3:21

  • @arindammandal7742
    @arindammandal7742 7 років тому

    faltu