Introduction to HashMap & HashTable in Java

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  • เผยแพร่เมื่อ 26 พ.ย. 2024

ความคิดเห็น • 157

  • @KunalKushwaha
    @KunalKushwaha  4 หลายเดือนก่อน +5

    DSA + interview preparation playlist: th-cam.com/play/PL9gnSGHSqcnr_DxHsP7AW9ftq0AtAyYqJ.html

  • @ABHILASHHAMSA
    @ABHILASHHAMSA 7 หลายเดือนก่อน +23

    00:05 Introduction to HashMap & HashTable in Java
    02:06 Hashmaps provide a way to search for elements in constant time.
    06:43 HashMap in Java is a key-value pair data structure that allows fast retrieval of values based on their keys.
    09:12 HashMap and HashTable are used in various areas such as programming languages, network routers, virtual memory, cryptography, and string search.
    14:58 Introduction to HashMap & HashTable in Java
    17:36 In Java, hash code is a method used to convert a string or number into a unique integer value.
    22:34 Hashing is used to reduce large numbers to fit within a predefined range.
    24:52 Collision in HashMap and HashTable occurs when multiple indices have the same hash code.
    29:39 Assumption of simple uniform hashing for equal likelihood of keys being hashed to any slot in the table.
    32:04 The hash function used is k modulo m.
    37:41 Understanding the universal hashing method
    40:23 The size of the table should be dynamically adjusted based on the number of elements.
    45:29 Inserting elements in a HashMap has an average constant time complexity of O(n)
    48:51 Open addressing is a method to prevent collisions in HashMap & HashTable.
    54:07 Double hashing is used to avoid clustering in hash tables.
    56:56 Hashmaps in Java: Understanding the internal workings of hashmaps
    1:02:17 Open addressing is efficient in terms of cache performance and memory usage
    1:05:06 Open addressing in HashMap degrades past 70% due to clustering and array size reduction.
    1:09:39 Introduction to HashMap & HashTable in Java
    1:13:30 HashMap vs HashTable in Java
    1:18:38 Introduction to HashMap & HashTable in Java
    1:21:31 HashMap can be used to remove a key from the map.
    1:28:18 Introduction to HashMap & HashTable in Java
    1:31:29 Understanding the basic operations of HashMap and HashTable in Java
    1:37:28 Introduction to HashMap & HashTable in Java
    1:39:30 HashMap and HashTable are important data structures in Java.
    --------- Definitely his way of teaching lets the topic sink-in in much better way, here are some timestamps.

  • @aakashsharma8086
    @aakashsharma8086 ปีที่แล้ว +89

    A very talented teacher with no haters

    • @sachinmishra803
      @sachinmishra803 ปีที่แล้ว +1

      😂😂

    • @Ajeetkumar-uo4hf
      @Ajeetkumar-uo4hf หลายเดือนก่อน +1

      Once he started teaching dsa chabbar,babber, driver all started hating him beacuse of obvious reason they cannot match his teaching standard

  • @chiraagb
    @chiraagb 9 หลายเดือนก่อน +3

    8:45 Applications of hashmaps so that lookup is in O(1)
    1) Symbol Table {a table where each variable is pointed to its data type and the value in short} (in compilers {C++, Java} and interpreter {Python, JS})
    2) Network Routers {routing the IP addresses} , Port to IP binding
    3) Cryptography
    4) String search (grep command)

  • @dattajadhav5705
    @dattajadhav5705 ปีที่แล้ว +23

    He is the guy who can compromise with setup but not with quality of content and explanation 💫💫💫

  • @Coding-Just
    @Coding-Just ปีที่แล้ว +14

    Kunal is not just a mentor he is person who help us to achieve our goals without any fake suggestions.

  • @WiseCoderWhoLifts
    @WiseCoderWhoLifts 4 วันที่ผ่านมา

    One of the best Data structure TBH. The versatility of hashmaps is insane.

  • @vinayakjaiswal9976
    @vinayakjaiswal9976 ปีที่แล้ว +32

    Kunal bhaiya one request while making these DSA videos also mention 3-4 projects in which these data structure has helped you and how😊

    • @elco7956
      @elco7956 ปีที่แล้ว +19

      I don't think stuff like this is used in development on a daily basis
      DSA and Leetcode help you learn how to think like a programmer and are needed to clear interview rounds in big tech companies, but you will not really be inverting binary trees all day once you get a job as a SWE

  • @thesavageindian5136
    @thesavageindian5136 ปีที่แล้ว +15

    Thanks a lot kunal Bhaiyya ❤
    Please increase the pace of this course because we are getting paused while learning due to long gaps of new videos

  • @notjod4948
    @notjod4948 ปีที่แล้ว +9

    When He teaches things gets simpler !
    Thanks Kunal Bro!

  • @vaibhavimishra763
    @vaibhavimishra763 ปีที่แล้ว +2

    Best best best course even paid course can't beat this DSA course ❤❤❤

  • @pratikpalve-j8u
    @pratikpalve-j8u 19 วันที่ผ่านมา

    Starting with an Empty Binary Search Tree(BST),create a BST by reading the values in the given
    Order and perform following operations on it: 1. Insert a new node 2. Perform Inorder, Preorder
    And Postorder Traversals 3. Search 4. Delete 5. Height 6. Mirror Image 7. Find Smallest and
    Largest Element .
    In this question we implemented some operation but some are left such as mirror image, Height , Find Smallest and
    Largest Element .

  • @nareshkamurthi05
    @nareshkamurthi05 ปีที่แล้ว +6

    Please Complete DSA as soon as possible

  • @techiesworld2112
    @techiesworld2112 ปีที่แล้ว +3

    Had been waiting for this kunal bhai..thank you very much❤

  • @pozo-r1x
    @pozo-r1x 5 หลายเดือนก่อน +6

    is this a live video?......people take 100s of cuts in their video to give the content and you are making a lecture live and the content you provide is really so top notch...................really need your type of mentor on this platform....................you are really great kunal bhaiya......................your content is far more better than millions subscriber youtube channel........................i save my 100s of hours by seeing your lectures....................hope you continue this great work of spreading knowledge🙌🙌🙌🙌🙌🙌🙌🙌😊😊😊😊😊😊

  • @uyinokuta3083
    @uyinokuta3083 9 หลายเดือนก่อน +53

    This is soooooo complicated and difficult to understand 😭😭😭😭

  • @darshanbs2267
    @darshanbs2267 8 หลายเดือนก่อน

    You are just amazing kunal really i dindt understood dsa in my college better than here

  • @GouravKumar-ep3hr
    @GouravKumar-ep3hr 9 หลายเดือนก่อน

    Thanks for teaching us for free, explaining the complex concept with simple & easy approach.

  • @pratikpalve-j8u
    @pratikpalve-j8u 19 วันที่ผ่านมา

    consider following questions please
    Implement a program to represent a graph using adjacency matrix and adjacency list, compute
    DFS and BFS of the same

  • @dhruvdangi_
    @dhruvdangi_ ปีที่แล้ว +12

    This video come out at 2 Am in India
    And I am gonna watch it in 2 am

  • @satyampandey3136
    @satyampandey3136 หลายเดือนก่อน

    Thank you so much for helping with these awesome work. Best course!!

  • @Hamim-Talukdar
    @Hamim-Talukdar ปีที่แล้ว +1

    Thanks a lot Kunal vi for giving video again🔥Love from Bangladesh💙

  • @LavKushwaha
    @LavKushwaha ปีที่แล้ว +6

    King Uploaded His DSA VIDEO AT 2 AM 🥷❤️‍🔥
    #DSAWithKunal

    • @Nameiscantsay
      @Nameiscantsay 5 หลายเดือนก่อน +5

      Bro he lives in London so he didn't upload this video at 2 AM

  • @Isagi__000
    @Isagi__000 ปีที่แล้ว

    Thanks for still doing it. We are lucky to have you

  • @SanjayPatel01
    @SanjayPatel01 ปีที่แล้ว +2

    Thank you sir for uploading the video ❤

  • @kirangowda8506
    @kirangowda8506 หลายเดือนก่อน

    I love watching your videos, bro. Thank you so much for providing excellent content !!!!!!

  • @andretheruler714
    @andretheruler714 ปีที่แล้ว +1

    the mere fact that you got 88/100 and you didn't consider that a good grade, shows the level you are at, god tier

  • @rupashreescanvas2562
    @rupashreescanvas2562 ปีที่แล้ว +1

    Thank you so much Kunal da,for uploading the rest parts gradually.

  • @Akhil_NK
    @Akhil_NK ปีที่แล้ว +3

    BHAIYA on a serious note your videos are seriously means seriously great but bhiaya plz as a freasher its almost impossible to chose which topic to learn first can you plz prepare a road map for this playlist on java + dsa plzzz
    please note this bhaiya

    • @KunalKushwaha
      @KunalKushwaha  ปีที่แล้ว +7

      just follow the playlist order

  • @xtttra
    @xtttra 5 หลายเดือนก่อน +2

    simple, very easy, very simple stuff

  • @BrxkenBxT
    @BrxkenBxT ปีที่แล้ว +2

    Thanks a lot Man!
    Nobody expected that you'll upload 3-4 videos together....
    Hats off to your efforts🫡🫡

  • @shashankpratapwar-wj7xl
    @shashankpratapwar-wj7xl ปีที่แล้ว

    The Messiah of dsa for beginners❤

  • @innovativethinker797
    @innovativethinker797 ปีที่แล้ว

    Nice lecture lot of new things learnt from this lecture good👍 ahead bro and share your knowledge📚. It's very helpful for students who are curious about learning DSA stuffs

  • @aryanarora9324
    @aryanarora9324 ปีที่แล้ว +2

    I was just searching for Hashing from Kunal. Dint found the video and now he uploaded it 😂

  • @pratikpalve-j8u
    @pratikpalve-j8u 19 วันที่ผ่านมา

    Please make video on graph
    Graph : Concept and terminologies, Graph as an ADT, Representation of graphs using adjacency matrix
    and adjacency list, Breadth First Search traversal, Depth First Search traversal, Prim’s and Kruskal’
    algorithms for minimum spanning tree, Shortest path using Dijkstra's algorithm.
    Hash Table: Hash Table- Concepts-hash table, hash function, bucket, collision, overflow, open hashing,
    closed hashing, perfect hash function, hash functions- properties of good hash function, division,
    multiplication, extraction, mid-square, folding and universal, Collision resolution strategies- open addressing
    and chaining without replacement, open addressing and chaining with replacement. Multiway Trees: B-Tree,
    B+ Tree.
    please make videos on above topic only those topic left in DSA. please

  • @SidhuMoosewala-u7i
    @SidhuMoosewala-u7i ปีที่แล้ว +1

    Bro I have been waiting for this video or a longtime ,this video push my motivation to a new level

  • @harigs72
    @harigs72 หลายเดือนก่อน

    35:00
    Division
    Multiplication
    Universal

  • @sachinsingh6244
    @sachinsingh6244 ปีที่แล้ว

    Waiting for next Video ❤ this was lit🔥🔥🔥as always!

  • @biswajeetyadav
    @biswajeetyadav หลายเดือนก่อน

    you are the best kunallllll

  • @upsidedown6204
    @upsidedown6204 11 หลายเดือนก่อน

    Thank you bhaiya ! for such an amazing lecture.

  • @geetanshkaul3419
    @geetanshkaul3419 ปีที่แล้ว +2

    FINALLLLLYYYYYYYYYYYY

  • @abhinavmathur311
    @abhinavmathur311 ปีที่แล้ว

    22:00 amortized constant time
    25:48: collision resolve: chaining---
    30:30 simple uniform hashing
    41:23 size of table
    47:07 amortized/average constant time explained
    50:00 collision resolve-open adressing

  • @abhinavmathur6072
    @abhinavmathur6072 ปีที่แล้ว

    Thanks bro... been waiting for it since long time

  • @abhishekkgupta4294
    @abhishekkgupta4294 ปีที่แล้ว

    was waiting for it love your video Kunal

  • @sourabhkumar5815
    @sourabhkumar5815 ปีที่แล้ว

    Appreciate your efforts Kunal. 🙌

  • @curiosity600
    @curiosity600 ปีที่แล้ว

    Excellent Sir!
    Keep teaching Sir🤲

  • @AnimeshPal-j2f
    @AnimeshPal-j2f หลายเดือนก่อน

    Hey Kunal, I'm watching and learning from your DSA course. But, unable to find your Dynamic Progamming content/series.
    Can you please share the playlist link for Dynamic Programming ?

  • @faizaankhan8090
    @faizaankhan8090 ปีที่แล้ว

    Thanks a lot Kunal. Your videos helped me a lot!

  • @vaishnavikammara8047
    @vaishnavikammara8047 4 หลายเดือนก่อน

    Thank you for the playlist, came way to far with the playlist and waiting for graphs and DP to grasp the knowledge.😄

    • @calvinripley9093
      @calvinripley9093 3 หลายเดือนก่อน

      Bro I really don't think he'll make those videos we need to refer some other Java Coding channels, if you get it please share it here, but Kunal Kushwaha's DSA is amazing it's missing only dp and graphs

  • @sagarsunar6501
    @sagarsunar6501 4 หลายเดือนก่อน

    Impressive teachings!!!

  • @arab2aljaafary72
    @arab2aljaafary72 ปีที่แล้ว

    great teacher ..respect from syria🧡

  • @lostquasar6899
    @lostquasar6899 2 หลายเดือนก่อน

    I love this man so much

  • @kalairoxan2398
    @kalairoxan2398 14 วันที่ผ่านมา

    21:56 first time i saw kunal make tease others 😂

  • @Devnpatel001
    @Devnpatel001 ปีที่แล้ว +3

    Hii,
    I am studying this DSA course from Canada🇨🇦 and I am in high school right now,
    I have one question that after completing this Java DSA course do I need to learn anything more to get ready for a job??
    I need some guidance,
    Pls be helpful 😊

    • @krishanrajoriya
      @krishanrajoriya ปีที่แล้ว +2

      You should do development also...

    • @Devnpatel001
      @Devnpatel001 ปีที่แล้ว +1

      Thanks a lot for ur helpful reply😊👍

  • @PrashantShukla-n5e
    @PrashantShukla-n5e 10 หลายเดือนก่อน

    Great Lecture Loved it......

  • @riyabanerjee5599
    @riyabanerjee5599 ปีที่แล้ว +5

    46:04 I have a doubt when doubling the size of hashmap how is O(1+2+4+8...n) becomes O(n)

    • @KunalKushwaha
      @KunalKushwaha  ปีที่แล้ว +3

      Watch time complexity lecture

    • @i_habeeb
      @i_habeeb ปีที่แล้ว +1

      Constants and less dominatings are ignored

    • @ajitupadhyay3744
      @ajitupadhyay3744 5 หลายเดือนก่อน

      Sum of all powers of 2 up to N can be calculated as 2 log2(N) + 1 - 1.
      In this remove the constant value

    • @prpnow
      @prpnow 4 หลายเดือนก่อน

      ​@@ajitupadhyay3744 Hey I started coding this year should I start dsa ?

    • @sayantanmanna1360
      @sayantanmanna1360 3 หลายเดือนก่อน

      @@ajitupadhyay3744 still how can you remove the exponent 2^log2(N) ?

  • @ritikverma4480
    @ritikverma4480 5 หลายเดือนก่อน

    @KunalKushwaha I had one doubt that when we are trying to perform put operation and when our size / list.size > lf
    we are trying to rehash so the current item that we are trying to put will never be added to the original list ?

  • @samiranroyy1700
    @samiranroyy1700 ปีที่แล้ว +1

    Thanks sir ❤ pls come with dsa series

  • @gvikram3093
    @gvikram3093 5 วันที่ผ่านมา

    thank you

  • @ARYANKUMAR-gz2qw
    @ARYANKUMAR-gz2qw ปีที่แล้ว

    The real G.O.A.T 🔥

  • @exploring_my_world
    @exploring_my_world ปีที่แล้ว

    Thank you kunal bro❤

  • @CodeClarity01
    @CodeClarity01 3 หลายเดือนก่อน

    Thank you soo much❤

  • @preetichib2254
    @preetichib2254 11 หลายเดือนก่อน

    mind boggling but great stuff

  • @rho992
    @rho992 ปีที่แล้ว

    Hi Kunal do you have a video on Dynamic Programming

  • @ashutoshsingh-uh4io
    @ashutoshsingh-uh4io ปีที่แล้ว

    finally u r back

  • @MangekyouLevi
    @MangekyouLevi 10 หลายเดือนก่อน

    Great Video!

  • @Ajeetkumar-uo4hf
    @Ajeetkumar-uo4hf หลายเดือนก่อน

    DSA ka gunda Kunal ❤

  • @KunalKushwaha
    @KunalKushwaha  ปีที่แล้ว +6

    👉 Resources
    - Join Replit: join.replit.com/kunal-kushwaha
    - Lecture code: replit.com/@KunalsReplit/Hashmaps

    • @roshanchauhan1123
      @roshanchauhan1123 ปีที่แล้ว

      Thanks Kunal bhaiya ,, aap se contact me aana tha kya karu

  • @pratikbhange2757
    @pratikbhange2757 ปีที่แล้ว

    Thank you bro🙌

  • @VaibhavSharma-zj4gk
    @VaibhavSharma-zj4gk ปีที่แล้ว

    Thank you bro.

  • @poorpanda9033
    @poorpanda9033 ปีที่แล้ว

    Let's gooo

  • @yahyamohamoud7290
    @yahyamohamoud7290 ปีที่แล้ว

    Great video as usual

  • @karndeeps7547
    @karndeeps7547 ปีที่แล้ว

    Superb 🎉

  • @vishalvivekm
    @vishalvivekm ปีที่แล้ว +3

    First

  • @abhishekkgupta4294
    @abhishekkgupta4294 11 หลายเดือนก่อน

    kunal please make one practice leetcode questions video on hasmaps needed

  • @vijaybenz9741
    @vijaybenz9741 ปีที่แล้ว

    Amazing video

  • @sanjaysirangi9788
    @sanjaysirangi9788 ปีที่แล้ว

    Waiting for Advanced Tree questions and DP....❤

  • @ShoaibKhan-f5e
    @ShoaibKhan-f5e ปีที่แล้ว

    Thanks you so much bro

  • @sameerakhatoon9508
    @sameerakhatoon9508 ปีที่แล้ว

    Tysm!!🙏

  • @dattasaiupesh5157
    @dattasaiupesh5157 3 หลายเดือนก่อน +1

    does Interviewer asks implementation ?? im a beginner please reply

  • @Rajyadav-yh3rz
    @Rajyadav-yh3rz 4 หลายเดือนก่อน

    Amazing

  • @vishnupatil9444
    @vishnupatil9444 หลายเดือนก่อน

    kunal bhaiya please upload questions video

  • @avasthishan
    @avasthishan ปีที่แล้ว

    Hello, on the notepad please write on dark paper with a white ink.

  • @sinbad552
    @sinbad552 11 หลายเดือนก่อน +2

    21:55 where he trolls the over smart people is just too funny 😂

  • @kanny8742
    @kanny8742 ปีที่แล้ว +3

    Believe it or not, i am following his playlist from 2 years😂

  • @RidoyChandraDey
    @RidoyChandraDey 10 หลายเดือนก่อน +1

    Chaining and Open addressing part was so blurry for me. I am just feeling overwhelmed for it.

  • @piyushupreti8079
    @piyushupreti8079 ปีที่แล้ว +1

    Hey! Kunal I thought the next video you said would be of questions of binary tree

    • @KunalKushwaha
      @KunalKushwaha  ปีที่แล้ว

      I have posted that already and advance one will come as well

    • @piyushupreti8079
      @piyushupreti8079 ปีที่แล้ว +1

      With all due respect, When this series will be completed? It’s almost 2 years since the series was started

    • @raghvendrasingh1981
      @raghvendrasingh1981 10 หลายเดือนก่อน

      @@KunalKushwaha plz upload advance binary tree question

  • @preethamroyal5134
    @preethamroyal5134 ปีที่แล้ว

    Kunal can you please make a video on nested collections please!!!

  • @himanshusahu3969
    @himanshusahu3969 7 หลายเดือนก่อน

    how do i get this documentation ?

  • @jacksongeorge4047
    @jacksongeorge4047 ปีที่แล้ว

    Good one

  • @thechildofprophecy9135
    @thechildofprophecy9135 ปีที่แล้ว

    Finnally finnally finnally finnally FINNALLYYYYY 😭

  • @luffy_codes
    @luffy_codes 2 หลายเดือนก่อน

    where his setup gone? :/

  • @sarthakdhakade6603
    @sarthakdhakade6603 22 วันที่ผ่านมา

    Can anyone tell me how that h2(k) equals to 5... I mean how and why that is done in that way??

  • @rohanmallick2963
    @rohanmallick2963 ปีที่แล้ว

    Finally

  • @SajjadAhmed-lc2dr
    @SajjadAhmed-lc2dr 8 หลายเดือนก่อน

    there was bug coz size of list was increasing so when the value of size changes modulas will be different.

  • @RahulBisht_001
    @RahulBisht_001 ปีที่แล้ว

    Please upload DP video

  • @simalinaaz5640
    @simalinaaz5640 ปีที่แล้ว

    2am show💯❤️

  • @atomicgod1695
    @atomicgod1695 3 หลายเดือนก่อน +1

    1:17:38

  • @Akhil_NK
    @Akhil_NK ปีที่แล้ว +1

    BHAIYA on a serious note your videos are seriously means seriously great but bhiaya plz as a freasher its almost impossible to chose which topic to learn first can you plz prepare a road map for this playlist on java + dsa plzzz

    • @KunalKushwaha
      @KunalKushwaha  ปีที่แล้ว +1

      just follow the playlist order

  • @KavinduChinthaka
    @KavinduChinthaka 4 หลายเดือนก่อน

    🖤👌