Quick Sort For Beginners | Strivers A2Z DSA Course

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  • Опубликовано: 29 янв 2025

Комментарии • 533

  • @takeUforward
    @takeUforward  Год назад +206

    Let's march ahead, and create an unmatchable DSA course! ❤
    The worst case complexity will be O(N ^ 2) if we end up choosing the largest or smallest element as the pivot always. We will add this in the notes in the description. I missed this in the video.

    • @yashhokte1020
      @yashhokte1020 Год назад +10

      Yes striver , even i was thinking same that you didn't explain this thing , btw thankyou so much for this much crystal clear explaination ..

    • @anookimmidisetty2939
      @anookimmidisetty2939 Год назад +1

      Hi striver @takeUforward ,
      when are you going to release video solutions for string type problems and heaps?

    • @yaswanthmitta8983
      @yaswanthmitta8983 Год назад +11

      There is a minor mistake in your algo at 23:54 in while loop condition must be arr[i]

    • @teen_python_go9947
      @teen_python_go9947 9 месяцев назад +2

      Since, we are always choosing pivot to be the first element of the array, we can always avoid the O(n^2) case by pre-checking if the array is pre-sorted (with O(n) Time Complexity) and if it is not then only feed it into the quick sort function.

  • @yashsharma6112
    @yashsharma6112 Год назад +239

    I have to state it that "I tried to learn all sorting techniques various time. I learned but after a few days I forgot. But when you just added the real meaning of each sorting techniques. Like why it is called as selection sort and so on.... SO now I just remember their meanings and write the algorithm on my own." Thank you very much. Loved your teaching style

  • @deepanshuthakur140
    @deepanshuthakur140 Год назад +79

    I tried to learn this from every yt channel but striver is the one i got it from, respect++

    • @navagharkiran5769
      @navagharkiran5769 4 месяца назад +1

      then you haven't tried Abdul Bari

    • @deepanshuthakur140
      @deepanshuthakur140 4 месяца назад +3

      @@navagharkiran5769 sadly I did, its not that abdul bari is not good, its me who is dumb uk but striver made me understand it anyhow

    • @parshuramry1657
      @parshuramry1657 4 месяца назад

      @@navagharkiran5769 abdul bari is better for college academics but striver is for campus selections

  • @kingreja5894
    @kingreja5894 Год назад +30

    //for descending
    while (arr[i]>=pivot && i

    • @PunjabPrank
      @PunjabPrank 27 дней назад

      yes i am thinking about this mistake ..thank you

  • @Kaushik846
    @Kaushik846 Год назад +31

    Probably one of the crisp and to the point explanation of quick sort algorithm available online!!

  • @omkarsawant9267
    @omkarsawant9267 Год назад +44

    Quick Sort's in-place partitioning makes it more memory-efficient than Merge Sort in practice, but the worst-case space complexity can be higher when the partitioning is unbalanced.
    Time Complexity:
    Best Case: O(n log n) when the pivot choices consistently lead to balanced partitions.
    Average Case: O(n log n)
    Worst Case: O(n^2) when the pivot choices consistently lead to unbalanced partitions. However, with good pivot selection strategies (e.g., using the median element), this can be mitigated.
    Space Complexity:
    O(log n) auxiliary space for the recursive call stack in the best and average cases.
    O(n) in the worst case when the partitioning is highly unbalanced.
    Quick Sort's in-place partitioning makes it more memory-efficient than Merge Sort in practice, but the worst-case space complexity can be higher when the partitioning is unbalanced.
    Quick Sort tends to perform well in practice and is often faster than other O(n log n) algorithms, but its worst-case time complexity is worse than Merge Sort.
    Merge Sort's space complexity makes it less memory-efficient compared to some other sorting algorithms, but its stable performance and guaranteed O(n log n) time complexity in all cases make it a preferred choice for certain scenarios.
    Space Complexity:
    O(n) additional space is required for the temporary arrays during the merging process.
    It has a space complexity of O(n) due to the need for additional space for merging.

    • @Jinntechive
      @Jinntechive 9 месяцев назад +1

      Appreciate the effort you put for writing this comment 😇❤

    • @nayankhuman1043
      @nayankhuman1043 7 месяцев назад +1

      Thanks for the comment. i was looking for it.

    • @dreamer12n
      @dreamer12n 5 месяцев назад

      Hey can you give me the code for pivot = median element pls??

    • @onlyone7209
      @onlyone7209 3 месяца назад

      ​@@dreamer12nwhat kind of code do you want

    • @itsmehere8285
      @itsmehere8285 2 месяца назад +1

      ​@@dreamer12nJust set pivot = (low + high)/ 2 or in a better way to deal with larger numbers make it low +(high -low)/2

  • @ParasSharma-mf8or
    @ParasSharma-mf8or Год назад +47

    Thanks for this amazing lecture,this is my humble request please complete this course as soon as possible.

  • @adityamaheshwari4250
    @adityamaheshwari4250 Год назад +21

    Really you make everything a cakewalk!
    Thank you so much sir, it takes a big heart to do such a lot for the community for free❤

  • @isaacreyes7563
    @isaacreyes7563 6 месяцев назад +3

    Damn, I have been looking at sort, recursion, etc forever. I was first confronted with merge/quicksort back in 2019. Been looking at them from various other sources over the years but nobody ever explained it like you do. You are absolutely amazing at this stuff. Idk where you are in life but I hope you go onto make amazing things because someone with this in depth knowledge shouldn't be stuck teaching!

    • @tanmayjivnani865
      @tanmayjivnani865 5 месяцев назад +1

      Don't worry he is working at Google. Doing great in life :)

  • @parthmangalkar
    @parthmangalkar Год назад +5

    Understood!
    Thank you!! You are the best!
    Thanks a lot for making this DSA playlist! It really is helping me a lot!

  • @FunkyPanda6263
    @FunkyPanda6263 Год назад +31

    1 video every 2 days...
    Seems TRUE ❣️

  • @AdityaSharma-hs8os
    @AdityaSharma-hs8os Год назад +7

    please upload full course you are douing a good job bhaiyaaa ,you are really a honest teacher other youtubers who has million subscribers just make us fool on name of dsa course ,they just tell the problem and paste the soultion but you solve every aspect -f our doubt please cpmplete this and dont worry of views and watch time,time will come when everyone will know who is the best teacher on youtube for dsa

  • @animeshmishra6280
    @animeshmishra6280 Год назад +28

    how do you know which doubts are going to come in my mind. GREAT LECTURE SIR 🔥

    • @edisane8763
      @edisane8763 Год назад +6

      Because once he was also in the same place as we are now and he worked hard to reach this point now he is helping us

  • @ArunKumar-sk9jl
    @ArunKumar-sk9jl 6 месяцев назад

    A great man with the best of the best teaching skills and a kind attitude to make it free is awesome ❤

  • @tasneemayham974
    @tasneemayham974 Год назад +11

    CODE FOR DESCENDING (JAVA):
    public void quickSort(int[] arr, int low, int high){
    if(low low){
    j--;
    }
    if(i

    • @DineshKumar-pw7qb
      @DineshKumar-pw7qb Год назад

      When I try to run this code(using array), I getting no output and the code runs for infinite time. When I try with ArrayList, I am getting output.
      Explain why? This put me into severe headache

    • @tasneemayham974
      @tasneemayham974 Год назад

      @@DineshKumar-pw7qb Heyy!! You mean my code?
      Either way, can you send me the code you are working on. I want to try it. How about that? Maybe we can fix it together?

    • @DineshKumar-pw7qb
      @DineshKumar-pw7qb Год назад

      @@tasneemayham974bro are sure about your code is working well with array?

    • @tasneemayham974
      @tasneemayham974 Год назад

      @@DineshKumar-pw7qb Hey, mate! I copied my code, and yes it works with arrays. It doesn't give me errors or infinite loops, but...
      this line:
      while(arr[i] > pivot && i < high)
      I missed the =. I am so sorry. I should be:
      while(arr[i] >= pivot && i < high)
      Check it out now. But as I understand, the problem with your code is the array itself, yes? Not the output? If you want you can send the code. Because mine works well with array.
      P.S.: I will edit the original comment, and put the equal.

  • @pranshuatrey
    @pranshuatrey Год назад +5

    This is gold... Plz keep doing this..

  • @alessandrocamilleri1239
    @alessandrocamilleri1239 Год назад +8

    Excellent explanation as usual. Thank you.
    I am posting the iterative version which should further save on recursion call stack space. I have used a queue as the data structure but stack works just as well.
    void quickSort (vector &nums)
    {
    int n = nums.size();
    queue q;
    q.push({0, n-1});
    int low, high, pivot, i, j;
    while(!q.empty())
    {
    low = q.front().first;
    high = q.front().second;
    q.pop();
    if (low >= high) continue;
    pivot = nums[low];
    i = low; j = high;
    while (j > i)
    {
    while (nums[i] pivot && j > 0)
    j--;
    if (j >= i)
    swap(nums[i], nums[j]);
    }
    swap (nums[low], nums[j]);
    q.push({low, j-1});
    q.push({j+1, high});
    }
    }

    • @balakrishnanr648
      @balakrishnanr648 Год назад

      So Yah u tried the iterative version of Quick Sort but still you are using the space what the Recursive func calls use in func call stack in the QUEUE FORM. O(logN) Queue takes as extra space.
      Like the point is Quick sort no matter what -> You can further optimize. Func Stk Space or in Iterative normal stack or queue space is needed.
      As we need to store it somewhere -> what are the next range of places where it is unsorted.
      Either use the system's func call stack or make ur own.

  • @active_akasa8429
    @active_akasa8429 Год назад +3

    striver you are the best out of best....this tutorial is just amazing and you are like god for us A big thank you so much for your effort 🙂

  • @harishnaik8164
    @harishnaik8164 27 дней назад +5

    hence proved , Striver is GOAT.

  • @makerNg1817
    @makerNg1817 Год назад +2

    it's very understandable way you teach. thank you for this amazing lecture

  • @tanmaykarmakar6224
    @tanmaykarmakar6224 Год назад +24

    Quick sort in Descending order-(PYTHON)
    arr=[25,1,8,7,32,2,5]
    def piviot(arr,high,low):
    piviot=arr[high]
    i=high
    j=low
    while(i=piviot and i

    • @sumitapathak2900
      @sumitapathak2900 Год назад +6

      Hey I haven't done a dryrun of your code but as i has index of high how can in increment in the while loop?

    • @jayaveersai1446
      @jayaveersai1446 Год назад +1

      yes make sense and have to chnage the while (i

    • @nirmaljyotibiswas752
      @nirmaljyotibiswas752 3 месяца назад

      shouldn't it be while(i > j) ?

  • @mityamkumar1158
    @mityamkumar1158 Год назад +3

    Understood.... 💯💯 Excited for Arrays playlist❤

  • @Manishgupta200
    @Manishgupta200 Год назад +13

    Here is my Assignment question solution :
    #include
    using namespace std;
    int partition(vector &arr, int low, int high){
    int pivot = arr[low];
    int i = low;
    int j = high;
    while(i < j){
    while(arr[i] >= pivot && i = low + 1) j--;
    if(i < j) swap(arr[i], arr[j]);
    }
    swap(arr[low], arr[j]);
    return j;
    }
    void qs(vector& arr, int low, int high){
    if(low < high){
    int pIndex = partition(arr, low, high);
    qs(arr, low, pIndex - 1);
    qs(arr, pIndex + 1, high);
    }
    }
    int main(void){
    // vector v = {4, 3, 2, 1};
    vector v = {4, 3, 2, 1, 4, 7, 5, 6};
    int n = v.size();
    qs(v, 0, n-1);
    for(auto it : v) cout

  • @Manoj_IIC-Admin
    @Manoj_IIC-Admin Год назад +23

    at time 23:52 it should be pivot not ar[pivot] thanks bhaiya

  • @keshariaman
    @keshariaman Год назад +5

    Thanks a lot for Quick Short. Feels easier to understand 🥰

  • @ShivamGupta-xw6gh
    @ShivamGupta-xw6gh Год назад +1

    best explanation of quick sort on youtube

  • @darkelixir2517
    @darkelixir2517 Год назад +2

    Understood, will be a quick way to remember the algorithm, well taught!! Thanks

  • @rajkumarvb5197
    @rajkumarvb5197 Год назад +1

    Manhhhh 🥵, you are awesome. I can see the effort you are putting in! Thanks a lot! ❤

  • @CodeBoost8375
    @CodeBoost8375 Год назад +4

    Thanks for recursive effort brother.And till now all your lectures are absolutely awesome 🔥🔥

  • @ahssanakhtar5746
    @ahssanakhtar5746 8 месяцев назад

    Excellent content about DSA .I am follwing you A-Z coarse and improve my self in DSA day by DSA Thanks for making such a amazing content

  • @SharathS-s9i
    @SharathS-s9i 4 месяца назад

    for the assigment problem just change the condition while (i < j) {
    while (arr[i] > pivot && i

  • @gurudev8543
    @gurudev8543 Год назад +3

    Best explanation ever ❤️❤️❤️
    Thanks bhaiya

  • @madhumithaakula7666
    @madhumithaakula7666 3 месяца назад +1

    Thank You anna because of u I have learned something new today🙂

  • @subhadeepghosh2813
    @subhadeepghosh2813 Год назад +1

    Kaha se sikha hai aise padana?
    vai koi vi nahi hai tumhare jaisa.
    Maza aa gaya

  • @shubhamagarwal1434
    @shubhamagarwal1434 6 месяцев назад +9

    #Free Education For All...... # Bhishma Pitamah of DSA...You could have earned in lacs by putting it as paid couses on udamey or any other elaerning portals, but you decided to make it free...it requires a greate sacrifice and a feeling of giving back to community, there might be very few peope in world who does this...."विद्या का दान ही सर्वोत्तम दान होता है" Hats Off to you man, Salute from 10+ yrs exp guy from BLR, India.......

  • @AniketSingh-gm9nh
    @AniketSingh-gm9nh 6 месяцев назад

    u r just amazing. keep educating man u r blessing for us.❤

  • @rayyanrahim7413
    @rayyanrahim7413 Год назад +2

    love from pakistan we need these type of legend to teach progamming

  • @shubhamsahu492
    @shubhamsahu492 2 месяца назад

    Your explanations are the best 💕👌👌

  • @tusharkhandave374
    @tusharkhandave374 Год назад

    Thanks for giving this content for free it helps me a lot

  • @manish_mnnit
    @manish_mnnit Год назад +2

    For Descennding Order Sorting ->
    //Just Reverse the inequality sign in partition function :-
    #include
    int partition(vector&arr,int low,int high){
    int pivot =arr[low];
    int i=low ,j=high;
    while(i

  • @abdulwahabshaik1686
    @abdulwahabshaik1686 Год назад

    Understanding everything u r teaching to us u r magician striver

  • @DeepakKumar-xj4ul
    @DeepakKumar-xj4ul 10 месяцев назад

    for decreasing Quick Sort:-
    int partition(vector &arr, int low, int high) {
    int pivot = arr[low];
    int i = low;
    int j = high;
    while (i < j) {
    while (arr[i] >= pivot && i = low + 1) {
    j--;
    }
    if (i < j) {
    swap(arr[i], arr[j]);
    }
    }
    swap(arr[low], arr[j]);
    return j;
    }
    void quickSort(vector &arr, int low, int high) {
    if (low < high) {
    int pIndex = partition(arr, low, high);
    quickSort(arr, low, pIndex - 1);
    quickSort(arr, pIndex + 1, high);
    }
    }
    vector sortArray(vector &arr) {
    quickSort(arr, 0, arr.size() - 1);
    return arr;
    }

  • @pradeep6635
    @pradeep6635 8 месяцев назад

    understood Bhayya.The best explanation in youtube😎

  • @SwatiSingh-ys6hm
    @SwatiSingh-ys6hm Год назад

    Damn it, i have learnt sorting algorithms a lot of times, but i aways manage to somehow forget.But after seeing this video now i understand it in so much more detail and depth which i earlier didn't even notice. thanks you soo much striver !

  • @samarthpai5359
    @samarthpai5359 4 месяца назад

    Understood sir.
    For descending order:
    int partitionFunction(int arr[], int low, int high){
    int i = low, j = high, temp;
    int pivot = arr[low];
    while(ipivot and i

  • @OmPrakash-268
    @OmPrakash-268 5 месяцев назад

    awesom explanation , love it learning DSA .

  • @tamoghnasaha2667
    @tamoghnasaha2667 Месяц назад

    Why we are using while (i

  • @cinime
    @cinime Год назад +1

    Understood! Super amazing explanation as always, thank you very much!!

  • @meshkatuddinahammed
    @meshkatuddinahammed Год назад

    Can't thank you more. Great lectures. Appreciate it.

  • @student_03
    @student_03 5 месяцев назад

    checking for out of bounds like this makes it simple and natural
    while (i pivot) {
    j--;
    }

  • @onetapgaming123-v2x
    @onetapgaming123-v2x 5 месяцев назад +8

    16 Aug 2024, 2:00 a.m.🎯🔥

  • @Gurunat16
    @Gurunat16 7 месяцев назад +4

    26:58 That will be |1 3 2| 4. Right?

  • @AbhishekKumar-cd4gg
    @AbhishekKumar-cd4gg Год назад

    // for descending order
    just we have to do the tweaks in the how we are selecting elements when which we are stopping when we are finding element smaller in left and stop when we find the element greater the pivot then we just we swap it
    than it goes in the recursion stack
    public class Quicksort {
    static int partiton(int arr [] , int low , int high ){
    int pivot = arr[low];
    int i= low;
    int j = high;
    while (i < j ) {
    while (arr[i] >= pivot && i = low + 1 ) {
    j--;
    }
    if(i < j ){
    int temp = arr[i];
    arr[i] = arr [j];
    arr[j] = temp;
    }
    }
    int temp = arr[j];
    arr[j] = arr[low];
    arr[low] = temp;
    return j ;
    }
    static void quicksort(int arr [] , int low , int high){
    if(low < high ){
    int PartionIndex = partiton(arr,low,high) ;

    quicksort(arr, low , PartionIndex-1);
    quicksort(arr, PartionIndex+1 , high);
    }

    }
    public static void main(String[] args) {
    int arr [] = {10, 80, 30, 90, 40};
    int n = arr.length-1;
    quicksort(arr, 0, n);
    for (int i : arr) {
    System.out.print(i + " ");
    }
    }
    }

  • @sonalikharwar4269
    @sonalikharwar4269 Год назад +5

    Instead of 3,2,1 it should be 1,3,2 coz we have done swapping b/w 4 & 1 like swap(arr[low], arr[j]) right ?

  • @rohanraj2604
    @rohanraj2604 Год назад

    Crystal clear bhaiya 😍

  • @zyzzbrah9429
    @zyzzbrah9429 7 месяцев назад +1

    int partition (int arr[], int low, int high)
    {
    int p=arr[low];
    int i=low,j=high;
    while(i=p && i

    • @shailesh3348
      @shailesh3348 7 месяцев назад

      I also completed 2 steps can we connect?

  • @hemantyadav6198
    @hemantyadav6198 27 дней назад

    Awesome explaintion ❤

  • @scoc55vora15
    @scoc55vora15 Год назад

    Best , Detailed and Crisp

  • @shivamcanada
    @shivamcanada 5 месяцев назад

    very well explained brother appreciate your efforts

  • @Malayalam_learner
    @Malayalam_learner 22 дня назад

    Why not
    ilow
    Can anyone explain why striver doesn't take these ??

  • @hareshnayak7302
    @hareshnayak7302 9 месяцев назад

    Understood,Thanks striver for this amazing video.

  • @rishabhkumar-qs3jb
    @rishabhkumar-qs3jb 9 месяцев назад +1

    Excellent explanation :)

  • @manavsingh5919
    @manavsingh5919 Год назад

    Understood sir.....u r the best👍💞

  • @yashlakade179
    @yashlakade179 Месяц назад +1

    Thanks Striver :)

  • @preetisahani5054
    @preetisahani5054 Год назад +1

    Its a great video, but you should also explain the cases where complexity for quick sort can result to O(n^2) in the case where all elements of array are same and when array is already sorted, in those cases partition will always be 1, n-1.

    • @krishnendughosh2368
      @krishnendughosh2368 Год назад

      sorted or even if sorted in descending order complexity will be n^2

  • @AbdullahKhan-et6qo
    @AbdullahKhan-et6qo Год назад

    Was eagerly waiting for your videos 🙌

  • @nyx1284
    @nyx1284 5 месяцев назад

    by the way, there exist some examples where the code shown can return in out of vector subscript error because the partition index might be returned as 0 and when we try to access pIndex-1 it will of course crash. so put an extra little check where the code just returns if pIndex is 0.

  • @diyaarora3199
    @diyaarora3199 Год назад

    Wonderful Explanation!!
    Notes include the space complexity as O(1)+O(N) auxiliary stack space. Is it the worst case space complexity? And is the best and average case auxiliary space complexity O(logN)?

  • @nikhild.20
    @nikhild.20 Год назад

    Code for descending order :-
    #include
    int fn(vector &arr,int low, int high){
    int pivot = arr[low];
    int i = low;
    int j = high;
    while(i=pivot && i

  • @soumelee5661
    @soumelee5661 Год назад

    Awesome explanation! TYSM for the videos

  • @sugarfreecode
    @sugarfreecode Год назад +1

    Quick Sort in Descending Order (C++):
    int partitionArray(int input[], int start, int end) {
    int pivot = input[start];
    int i = start;
    int j = end;
    while (i < j) {
    while (input[i] >= pivot && i < end) {
    i++;
    }
    while (input[j] < pivot && j > start) {
    j--;
    }
    if (i < j) {
    int temp = input[i];
    input[i] = input[j];
    input[j] = temp;
    }
    }
    input[start] = input[j];
    input[j] = pivot;
    return j;
    }
    void quickSort(int input[], int start, int end) {
    if (start >= end) return;
    int partition = partitionArray(input, start, end);
    quickSort(input, start, partition - 1);
    quickSort(input, partition + 1, end);
    }

  • @bonammadankumar681
    @bonammadankumar681 11 месяцев назад

    You rocks the DSA

  • @CycoTrend
    @CycoTrend 26 дней назад

    bro is the angel!

  • @twopiebytwo
    @twopiebytwo Год назад

    Quicksort in python.
    def partition(L,lower,upper):
    i=lower
    pivot=L[lower]

    for j in range(lower+1,upper+1):
    if(L[j]

  • @Hipfire786
    @Hipfire786 10 месяцев назад

    understood everything sir so far all sorting techniques

  • @WellbeingWarior
    @WellbeingWarior 5 месяцев назад

    Quick sort in Descending order in Python:
    def qS(array):
    if len(array) pivot]
    return qS(elm_grater_than_pivot) + elm_equal_pivot + qS(elm_less_than_pivot)

  • @THE-MYSTIC
    @THE-MYSTIC Год назад +1

    Thanks striver this video helped me ❤

  • @Kirito045
    @Kirito045 Год назад

    Understood
    Striver on TOP!

  • @sumit49
    @sumit49 Год назад

    us!!
    please add it in the same playlist as that will be more organised .
    ❣❣

  • @yhbarve
    @yhbarve Год назад +1

    Understood bhaiya! Thank you

  • @lwnflash2123
    @lwnflash2123 9 месяцев назад +2

    Is recursive stack space not required while computing space somplexity?

  • @SomnathMukherjee-ow6nl
    @SomnathMukherjee-ow6nl 8 месяцев назад

    23:27 why i

  • @sid17_cgdyt
    @sid17_cgdyt Год назад +2

    // condition i

    • @ShawnGrant-t9k
      @ShawnGrant-t9k 5 месяцев назад

      Yes you are right, it should evaluate this first as a precaution.

  • @sakshamtyagi2969
    @sakshamtyagi2969 11 месяцев назад

    Completely Understood 👍👍

  • @Gcoder18
    @Gcoder18 3 месяца назад

    nice way of explaination

  • @ProgrammerSalman031
    @ProgrammerSalman031 6 месяцев назад +1

    public:
    // Function to sort an array using quick sort algorithm in descending order.
    void quickSort(int arr[], int low, int high)
    {
    if (low < high) {
    int pIndex = partition(arr, low, high);
    quickSort(arr, low, pIndex - 1);
    quickSort(arr, pIndex + 1, high);
    }
    }
    public:
    int partition(int arr[], int low, int high)
    {
    int pivot = arr[low];
    int i = low;
    int j = high;
    int temp;
    while (i < j) {
    while (arr[i] >= pivot && i = low + 1) {
    j--;
    }
    if (i < j) {
    temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
    }
    }
    temp = arr[low];
    arr[low] = arr[j];
    arr[j] = temp;
    return j;
    }
    }

  • @mbkbishwokarma
    @mbkbishwokarma Год назад

    After checking all lectures on internet...None has explained better than you

  • @ByteBuilder-b6u
    @ByteBuilder-b6u 6 месяцев назад

    Should be include stack space in recursion problems while stating space complexity ?

  • @____Akash__
    @____Akash__ Год назад

    After long time ❤️❤️

  • @anuragpawar4497
    @anuragpawar4497 10 дней назад

    Step-2 completed! Understood

  • @joydeepdas29
    @joydeepdas29 Год назад +2

    Understood 😄. But will you please explain why we swapped between (arr[j] , arr[low]) instead of (arr[j], pivot)?

    • @takeUforward
      @takeUforward  Год назад +11

      I will recommend you to take examples and do a dry run, that will help you immensely to learn! I can answer, but finding out yourself on pen and paper is what will help you grow :)

    • @joydeepdas29
      @joydeepdas29 Год назад

      @@takeUforward Thank you. I will surely do as suggested 😄.

    • @elizabethr5161
      @elizabethr5161 Год назад +1

      We have taken low as a pivot, so it doesn't matter whether we swap it with low or pivot.

    • @Anonymous-ej2xo
      @Anonymous-ej2xo Год назад +3

      @@elizabethr5161 No it will matter because you want the swapping to occur between the elements of the array. With what you are saying, the j-th position will get the correct value, but 'low' position will not have been swapped. The swapping needs to occur in the array. You are getting confused as the values being swapped are effectively the same, but where the swap occurs is not the same.

    • @prajjwalkohli9830
      @prajjwalkohli9830 Год назад +4

      pivot is just some another independent variable having same value as arr[low], swapping with pivot means swapping values with an independent variable, we want swapping with the array's low itself so we explicitly use arr[low] here.

  • @lakshmitirupatamma2139
    @lakshmitirupatamma2139 Год назад

    Thank you so much sir for this content. Very good explanation

  • @diversestream66
    @diversestream66 7 месяцев назад

    for descending order
    const partition = (arr, low, high) => {
    let pivot = arr[low];
    let i = low;
    let j = high;
    while (i < j) {
    while (arr[i] >= pivot && i < high) {
    i++;
    }
    while (arr[j] low) {
    j--;
    }
    if (i < j) {
    let temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
    }
    }
    let temp = arr[low];
    arr[low] = arr[j];
    arr[j] = temp;
    return j
    };
    const quickSort = (arr, low, high) => {
    if (low < high) {
    let partitionIndex = partition(arr, low, high);
    quickSort(arr, low, partitionIndex - 1, high);
    quickSort(arr, partitionIndex + 1, high);
    }
    console.log(arr)
    };

  • @saranshgautam3011
    @saranshgautam3011 Год назад +2

    Why do we ignore recursion stack space when calculating Space Complexity? I think that should count.

  • @revathiP9185
    @revathiP9185 Год назад

    Thank you bhaiya. Amazing explanation ❤

  • @venkatesasrikanthdhulipala9486
    @venkatesasrikanthdhulipala9486 Год назад +2

    //Code for reversing the sorted array using quick sort
    // feel free to review
    class ReverseSortedArray {
    public static void main(String[] args) {
    int[] arr = {1,3,5,2,7,6,8,10};
    Qsort(arr,0,arr.length - 1);
    for(int i :arr){
    System.out.print(i + " ");
    }
    }
    public static void Qsort(int[] arr,int low,int high){
    if(low < high){
    int partition = parrtitionArrray(arr,low,high);
    Qsort(arr,low,partition - 1);
    Qsort(arr,partition + 1,high);
    }
    }
    static int parrtitionArrray(int[] arr,int low,int high){
    int val = arr[low];
    int i = low,j = high;
    while(i < j){
    while(val = low - 1){
    j--;
    }
    if(i < j){
    int temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
    }
    }
    int temp = arr[low];
    arr[low] = arr[j];
    arr[j] = temp;
    return j;
    }
    }

  • @Pawankumar-i8c
    @Pawankumar-i8c 3 месяца назад

    thank you so muchbhiaya for this masterpiece

  • @ankit-yj7hk
    @ankit-yj7hk 8 месяцев назад

    understand bhaiya !!!
    thank uh so much

  • @kalkeshvyas7897
    @kalkeshvyas7897 3 месяца назад

    yes all looks deep and good but recursion is tricky if we do 1 condition wrong very difficult to get it. In iterative its quite easy to get all.

  • @prithukathet193
    @prithukathet193 25 дней назад +1

    tusi great ho
    tofa Kabul karo.