Introduction to HashMap & HashTable in Java

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  • Опубліковано 15 січ 2025

КОМЕНТАРІ • 167

  • @KunalKushwaha
    @KunalKushwaha  5 місяців тому +5

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

  • @ABHILASHHAMSA
    @ABHILASHHAMSA 9 місяців тому +30

    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 Рік тому +96

    A very talented teacher with no haters

    • @sachinmishra803
      @sachinmishra803 Рік тому +6

      😂😂

    • @Ajeetkumar-uo4hf
      @Ajeetkumar-uo4hf 3 місяці тому +4

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

  • @Coding-Just
    @Coding-Just Рік тому +14

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

  • @dattajadhav5705
    @dattajadhav5705 Рік тому +24

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

  • @chiraagb
    @chiraagb 10 місяців тому +5

    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)

  • @vinayakjaiswal9976
    @vinayakjaiswal9976 Рік тому +34

    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 Рік тому +20

      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

  • @notjod4948
    @notjod4948 Рік тому +9

    When He teaches things gets simpler !
    Thanks Kunal Bro!

  • @CodeAndComplexity
    @CodeAndComplexity Рік тому +17

    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

  • @nareshkamurthi05
    @nareshkamurthi05 Рік тому +7

    Please Complete DSA as soon as possible

  • @G0host-07
    @G0host-07 11 днів тому

    Wow, Kunal! Your DSA playlist is absolutely phenomenal. The way you've explained each topic with such clarity and depth is truly commendable. This playlist is hands down one of the best resources for learning DSA on UA-cam. I've been following it for the past two months, and it has been incredibly helpful! However, I noticed that dynamic programming and graphs are yet to be covered. Could you please consider adding these topics? Completing them would make this course the ultimate DSA resource on UA-cam. Thank you so much for your hard work and dedication🙌🤝!

  • @vaibhavimishra763
    @vaibhavimishra763 Рік тому +2

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

  • @dhruvdangi_
    @dhruvdangi_ Рік тому +13

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

  • @WiseCoderWhoLifts
    @WiseCoderWhoLifts Місяць тому

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

  • @techiesworld2112
    @techiesworld2112 Рік тому +3

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

  • @xtttra
    @xtttra 6 місяців тому +2

    simple, very easy, very simple stuff

  • @darshanbs2267
    @darshanbs2267 10 місяців тому

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

  • @GouravKumar-ep3hr
    @GouravKumar-ep3hr 10 місяців тому

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

  • @Hamim-Talukdar
    @Hamim-Talukdar Рік тому +1

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

  • @LavKushwaha
    @LavKushwaha Рік тому +6

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

    • @Nameiscantsay
      @Nameiscantsay 7 місяців тому +5

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

  • @SanjayPatel01
    @SanjayPatel01 Рік тому +2

    Thank you sir for uploading the video ❤

  • @riyabanerjee5599
    @riyabanerjee5599 Рік тому +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  Рік тому +5

      Watch time complexity lecture

    • @i_habeeb
      @i_habeeb Рік тому +1

      Constants and less dominatings are ignored

    • @ajitupadhyay3744
      @ajitupadhyay3744 7 місяців тому

      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 6 місяців тому

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

    • @sayantanmanna1360
      @sayantanmanna1360 5 місяців тому

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

  • @rupashreescanvas2562
    @rupashreescanvas2562 Рік тому +1

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

  • @pozo-r1x
    @pozo-r1x 7 місяців тому +8

    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🙌🙌🙌🙌🙌🙌🙌🙌😊😊😊😊😊😊

  • @SidhuMoosewala-u7i
    @SidhuMoosewala-u7i Рік тому +1

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

  • @satyampandey3136
    @satyampandey3136 2 місяці тому

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

  • @kirangowda8506
    @kirangowda8506 3 місяці тому

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

  • @aryanarora9324
    @aryanarora9324 Рік тому +2

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

  • @uyinokuta3083
    @uyinokuta3083 11 місяців тому +58

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

  • @andretheruler714
    @andretheruler714 Рік тому +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

  • @BrxkenBxT
    @BrxkenBxT Рік тому +2

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

  • @Isagi__000
    @Isagi__000 Рік тому

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

  • @sagarsunar6501
    @sagarsunar6501 5 місяців тому

    Impressive teachings!!!

  • @geetanshkaul3419
    @geetanshkaul3419 Рік тому +2

    FINALLLLLYYYYYYYYYYYY

  • @curiosity600
    @curiosity600 Рік тому

    Excellent Sir!
    Keep teaching Sir🤲

  • @ParthDabhiOfficial
    @ParthDabhiOfficial 25 днів тому

    Helpful, Radhe Radhe

  • @sachinsingh6244
    @sachinsingh6244 Рік тому

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

  • @kalairoxan2398
    @kalairoxan2398 2 місяці тому

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

  • @shashankpratapwar-wj7xl
    @shashankpratapwar-wj7xl Рік тому

    The Messiah of dsa for beginners❤

  • @PrashantShukla-n5e
    @PrashantShukla-n5e Рік тому

    Great Lecture Loved it......

  • @harigs72
    @harigs72 2 місяці тому

    35:00
    Division
    Multiplication
    Universal

  • @innovativethinker797
    @innovativethinker797 Рік тому

    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

  • @arab2aljaafary72
    @arab2aljaafary72 Рік тому

    great teacher ..respect from syria🧡

  • @biswajeetyadav
    @biswajeetyadav 3 місяці тому

    you are the best kunallllll

  • @abhinavmathur6072
    @abhinavmathur6072 Рік тому

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

  • @upsidedown6204
    @upsidedown6204 Рік тому

    Thank you bhaiya ! for such an amazing lecture.

  • @Akhil_NK
    @Akhil_NK Рік тому +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

  • @sachin_dhakad823
    @sachin_dhakad823 Рік тому +2

    great course .....🫶

  • @pratikpalve-j8u
    @pratikpalve-j8u 2 місяці тому

    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 .

  • @AnimeshPal19
    @AnimeshPal19 3 місяці тому

    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 ?

  • @preetichib2254
    @preetichib2254 Рік тому

    mind boggling but great stuff

  • @DeepakBarajati
    @DeepakBarajati 28 днів тому +1

    please make video on graph and DP

  • @sinbad552
    @sinbad552 Рік тому +2

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

  • @samiranroyy1700
    @samiranroyy1700 Рік тому +1

    Thanks sir ❤ pls come with dsa series

  • @karndeeps7547
    @karndeeps7547 Рік тому

    Superb 🎉

  • @lostquasar6899
    @lostquasar6899 4 місяці тому

    I love this man so much

  • @faizaankhan8090
    @faizaankhan8090 Рік тому

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

  • @rho992
    @rho992 Рік тому

    Hi Kunal do you have a video on Dynamic Programming

  • @abhishekkgupta4294
    @abhishekkgupta4294 Рік тому

    was waiting for it love your video Kunal

  • @CodeClarity01
    @CodeClarity01 5 місяців тому

    Thank you soo much❤

  • @vaishnavikammara8047
    @vaishnavikammara8047 5 місяців тому

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

    • @calvinripley9093
      @calvinripley9093 4 місяці тому

      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

  • @thechildofprophecy9135
    @thechildofprophecy9135 Рік тому

    Finnally finnally finnally finnally FINNALLYYYYY 😭

  • @gvikram3093
    @gvikram3093 Місяць тому

    thank you

  • @sourabhkumar5815
    @sourabhkumar5815 Рік тому

    Appreciate your efforts Kunal. 🙌

  • @MangekyouLevi
    @MangekyouLevi Рік тому

    Great Video!

  • @vijaybenz9741
    @vijaybenz9741 Рік тому

    Amazing video

  • @Spark-uniQ
    @Spark-uniQ Рік тому

    Thank you kunal bro❤

  • @pratikbhange2757
    @pratikbhange2757 Рік тому

    Thank you bro🙌

  • @Rajyadav-yh3rz
    @Rajyadav-yh3rz 5 місяців тому

    Amazing

  • @sameerakhatoon9508
    @sameerakhatoon9508 Рік тому

    Tysm!!🙏

  • @VaibhavSharma-zj4gk
    @VaibhavSharma-zj4gk Рік тому

    Thank you bro.

  • @jacksongeorge4047
    @jacksongeorge4047 Рік тому

    Good one

  • @pratikpalve-j8u
    @pratikpalve-j8u 2 місяці тому

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

  • @ShoaibKhan-f5e
    @ShoaibKhan-f5e Рік тому

    Thanks you so much bro

  • @ARYANKUMAR-gz2qw
    @ARYANKUMAR-gz2qw Рік тому

    The real G.O.A.T 🔥

  • @ritikverma4480
    @ritikverma4480 7 місяців тому

    @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 ?

  • @Devnpatel001
    @Devnpatel001 Рік тому +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 😊

  • @abhishekkgupta4294
    @abhishekkgupta4294 Рік тому

    kunal please make one practice leetcode questions video on hasmaps needed

  • @yahyamohamoud7290
    @yahyamohamoud7290 Рік тому

    Great video as usual

  • @poorpanda9033
    @poorpanda9033 Рік тому

    Let's gooo

  • @braveboy1973
    @braveboy1973 День тому

    please anyone provide the documentation that the sir is following here

  • @dattasaiupesh5157
    @dattasaiupesh5157 5 місяців тому +1

    does Interviewer asks implementation ?? im a beginner please reply

  • @himanshusahu3969
    @himanshusahu3969 9 місяців тому

    how do i get this documentation ?

  • @pratikpalve-j8u
    @pratikpalve-j8u 2 місяці тому

    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

  • @piyushupreti8079
    @piyushupreti8079 Рік тому +1

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

    • @KunalKushwaha
      @KunalKushwaha  Рік тому

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

    • @piyushupreti8079
      @piyushupreti8079 Рік тому +1

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

    • @raghvendrasingh1981
      @raghvendrasingh1981 Рік тому

      @@KunalKushwaha plz upload advance binary tree question

  • @luffy-t9z
    @luffy-t9z 4 місяці тому

    where his setup gone? :/

  • @avasthishan
    @avasthishan Рік тому

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

  • @Ajeetkumar-uo4hf
    @Ajeetkumar-uo4hf 3 місяці тому

    DSA ka gunda Kunal ❤

  • @AnmolSingh-z7s9w
    @AnmolSingh-z7s9w 17 днів тому

    where is the interview questions of hashmap vidieo anybody tell

  • @vishnupatil9444
    @vishnupatil9444 3 місяці тому

    kunal bhaiya please upload questions video

  • @mjdev3314
    @mjdev3314 Рік тому

    ❤❤❤

  • @ashutoshsingh-uh4io
    @ashutoshsingh-uh4io Рік тому

    finally u r back

  • @KavinduChinthaka
    @KavinduChinthaka 5 місяців тому

    🖤👌

  • @preethamroyal5134
    @preethamroyal5134 Рік тому

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

  • @manashkhatowal7600
    @manashkhatowal7600 6 місяців тому

    nice

  • @simalinaaz5640
    @simalinaaz5640 Рік тому

    2am show💯❤️

  • @abhinavmathur311
    @abhinavmathur311 Рік тому

    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

  • @RidoyChandraDey
    @RidoyChandraDey 11 місяців тому +1

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

  • @RahulBisht_001
    @RahulBisht_001 Рік тому

    Please upload DP video

  • @sanjaysirangi9788
    @sanjaysirangi9788 Рік тому

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