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.
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.
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
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.
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
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!
00:06 - Quick sort is a sorting algorithm with time complexity of n log n and space complexity without using an extra temporary array. 04:36 - Pick up elements and place them in their correct place in a sorted array. 09:07 - The quick sort algorithm works by picking a pivot, placing it in its correct place, and recursively sorting the left and right arrays. 13:48 - Sorting an array using the partition index 18:43 - Quicksort algorithm explained in a simple way 22:51 - The algorithm involves partitioning an array based on a pivot element. 27:23 - Implementing the Quick Sort algorithm 31:23 - Quick sort algorithm has a time complexity of n log n and a space complexity of O(1).
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}); } }
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.
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
@@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 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.
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
#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.......
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)
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
// 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) ;
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 !
For Decending order #include using namespace std; int pick_place_pivot(int arr[],int low,int high){ int pivot=arr[low]; int i=low,j=high; while(i= pivot && i=low+1) j--; if(i> n; int arr[n]; for(int i=0;i> arr[i]; quick_sort(arr,0,n-1); for(int i=0;i
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; } }
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.
Everything will be same , only we have to do some changes in partition function to get array in decreasing order: int decendingPartition(int arr[],int low,int high){ int pivot=arr[low]; int i=low; int j=high; while(i=pivot && i
home work question (to print in decreasing order)- #include using namespace std; int partition(vector &arr, int low, int high){ int pivot=arr[low]; int i=low; int j=high; while(i=arr[low] && i
# code for reverse sorted i.e. descending sort def quickSort(self,arr,low,high): if low < high: p_index = self.partition(arr,low,high) self.quickSort(arr,low,p_index-1) self.quickSort(arr,p_index+1,high)
def partition(self,arr,low,high): # modified pivot = arr[high] i = low j = high while i < j: #modified while arr[i] >= pivot and i = low+1: j -= 1 if i < j: arr[i], arr[j] = arr[j], arr[i] arr[low], arr[j] = arr[j],arr[low] return j
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.
Yes striver , even i was thinking same that you didn't explain this thing , btw thankyou so much for this much crystal clear explaination ..
Hi striver @takeUforward ,
when are you going to release video solutions for string type problems and heaps?
There is a minor mistake in your algo at 23:54 in while loop condition must be arr[i]
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.
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
same here
same heree
same here
Same
Not same 😢
I tried to learn this from every yt channel but striver is the one i got it from, respect++
then you haven't tried Abdul Bari
@@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
@@navagharkiran5769 abdul bari is better for college academics but striver is for campus selections
//for descending
while (arr[i]>=pivot && i
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.
Appreciate the effort you put for writing this comment 😇❤
Thanks for the comment. i was looking for it.
Hey can you give me the code for pivot = median element pls??
@@dreamer12nwhat kind of code do you want
@@dreamer12nJust set pivot = (low + high)/ 2 or in a better way to deal with larger numbers make it low +(high -low)/2
Probably one of the crisp and to the point explanation of quick sort algorithm available online!!
Thanks for this amazing lecture,this is my humble request please complete this course as soon as possible.
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❤
1 video every 2 days...
Seems TRUE ❣️
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
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!
Don't worry he is working at Google. Doing great in life :)
00:06 - Quick sort is a sorting algorithm with time complexity of n log n and space complexity without using an extra temporary array.
04:36 - Pick up elements and place them in their correct place in a sorted array.
09:07 - The quick sort algorithm works by picking a pivot, placing it in its correct place, and recursively sorting the left and right arrays.
13:48 - Sorting an array using the partition index
18:43 - Quicksort algorithm explained in a simple way
22:51 - The algorithm involves partitioning an array based on a pivot element.
27:23 - Implementing the Quick Sort algorithm
31:23 - Quick sort algorithm has a time complexity of n log n and a space complexity of O(1).
Understood!
Thank you!! You are the best!
Thanks a lot for making this DSA playlist! It really is helping me a lot!
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
at time 23:52 it should be pivot not ar[pivot] thanks bhaiya
Yes bro.👊 😊
bro you are a true saviour !!
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});
}
}
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.
CODE FOR DESCENDING (JAVA):
public void quickSort(int[] arr, int low, int high){
if(low low){
j--;
}
if(i
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
@@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?
@@tasneemayham974bro are sure about your code is working well with array?
@@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.
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
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?
yes make sense and have to chnage the while (i
shouldn't it be while(i > j) ?
how do you know which doubts are going to come in my mind. GREAT LECTURE SIR 🔥
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
A great man with the best of the best teaching skills and a kind attitude to make it free is awesome ❤
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 🙂
This is gold... Plz keep doing this..
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
for the assigment problem just change the condition while (i < j) {
while (arr[i] > pivot && i
it's very understandable way you teach. thank you for this amazing lecture
Understood, will be a quick way to remember the algorithm, well taught!! Thanks
best explanation of quick sort on youtube
love from pakistan we need these type of legend to teach progamming
Understood.... 💯💯 Excited for Arrays playlist❤
Thanks a lot for Quick Short. Feels easier to understand 🥰
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
16 Aug 2024, 2:00 a.m.🎯🔥
#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.......
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;
}
Thanks for recursive effort brother.And till now all your lectures are absolutely awesome 🔥🔥
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)
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
Why can't we give while (i
Manhhhh 🥵, you are awesome. I can see the effort you are putting in! Thanks a lot! ❤
Best explanation ever ❤️❤️❤️
Thanks bhaiya
int partition (int arr[], int low, int high)
{
int p=arr[low];
int i=low,j=high;
while(i=p && i
I also completed 2 steps can we connect?
Thank You anna because of u I have learned something new today🙂
Understanding everything u r teaching to us u r magician striver
Thanks for giving this content for free it helps me a lot
checking for out of bounds like this makes it simple and natural
while (i pivot) {
j--;
}
26:58 That will be |1 3 2| 4. Right?
// 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 + " ");
}
}
}
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);
}
u r just amazing. keep educating man u r blessing for us.❤
Your explanations are the best 💕👌👌
Kaha se sikha hai aise padana?
vai koi vi nahi hai tumhare jaisa.
Maza aa gaya
understood Bhayya.The best explanation in youtube😎
Why we are using while (i
Thanks Striver :)
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 !
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 ?
Can't thank you more. Great lectures. Appreciate it.
Understood! Super amazing explanation as always, thank you very much!!
Understood,Thanks striver for this amazing video.
Crystal clear bhaiya 😍
awesom explanation , love it learning DSA .
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
Best , Detailed and Crisp
For Decending order
#include
using namespace std;
int pick_place_pivot(int arr[],int low,int high){
int pivot=arr[low];
int i=low,j=high;
while(i= pivot && i=low+1) j--;
if(i> n;
int arr[n];
for(int i=0;i> arr[i];
quick_sort(arr,0,n-1);
for(int i=0;i
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)
};
Quicksort in python.
def partition(L,lower,upper):
i=lower
pivot=L[lower]
for j in range(lower+1,upper+1):
if(L[j]
//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;
}
}
Understood bhaiya! Thank you
very well explained brother appreciate your efforts
Was eagerly waiting for your videos 🙌
Understood sir.....u r the best👍💞
Understood
Striver on TOP!
You rocks the DSA
Completely Understood 👍👍
Excellent explanation :)
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;
}
}
Why do we ignore recursion stack space when calculating Space Complexity? I think that should count.
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.
Awesome explanation! TYSM for the videos
// condition i
Yes you are right, it should evaluate this first as a precaution.
class Solution {
public static void quickSort(int[] arr,int low,int high) {
if(low
understood everything sir so far all sorting techniques
bro the worst case of quick sort is taking O(N^2) and in leet code giving the time limit exceed
understand bhaiya !!!
thank uh so much
After checking all lectures on internet...None has explained better than you
Is recursive stack space not required while computing space somplexity?
Java Code:
public class QuickSort {
public static void main(String[] args) {
int [] nums = {3,4,2,1,5,0};
quickSort(nums, 0, nums.length -1);
for(int element : nums){
System.out.print(element + " ");
}
}
public static void quickSort(int[] nums, int low, int high) {
if(low >= high) return ;
int partitionIndex = partition(nums,low,high);
quickSort(nums,low,partitionIndex-1);
quickSort(nums,partitionIndex +1, high);
}
public static int partition(int[] nums, int low , int high){
int pivot = nums[low];
int i = low, j = high;
while(i < j ){
while(i pivot) j--;
if(i < j) swap(nums, i, j);
}
swap(nums,low,j);
return j ;
}
public static void swap(int [] nums, int i , int j){
int temp = nums[i];
nums[i] = nums[j];
nums[j]= temp;
}
}
There's a mistake in pseudocode:
Timeline : 23:50
while((are[i] = low))
{
j++;
}
It will not be arr[pivot].
Yes!
can you please tell why it's giving wrong output for swapping this as
swap(arr[j], pivot) ; before return statement
@@simranbandhu9926 exactly...arr[low] and pivot is the same thing?? right?? then why its giving wrong output if we use pivot
@@takeUforward bhaiya please tell why is it giving wrong output if we use pivot instead of arr[low] just before return
, because the pivot itself, is an element and we have to swap the array value for which we need to write array[low]in place of pivot.
thank you so muchbhiaya for this masterpiece
you are my God , thanks man 🥰
Thanks striver this video helped me ❤
Everything will be same , only we have to do some changes in partition function to get array in decreasing order:
int decendingPartition(int arr[],int low,int high){
int pivot=arr[low];
int i=low;
int j=high;
while(i=pivot && i
After long time ❤️❤️
home work question (to print in decreasing order)-
#include
using namespace std;
int partition(vector &arr, int low, int high){
int pivot=arr[low];
int i=low;
int j=high;
while(i=arr[low] && i
Thank you so much sir for this content. Very good explanation
Reverse Sort need only 2 changes from original code :
while(arr[i]>=pivot && i
nice way of explaination
Understood...thank u sir🙂
understood , Step 2 completed :)
Thank you bhaiya. Amazing explanation ❤
# code for reverse sorted i.e. descending sort
def quickSort(self,arr,low,high):
if low < high:
p_index = self.partition(arr,low,high)
self.quickSort(arr,low,p_index-1)
self.quickSort(arr,p_index+1,high)
def partition(self,arr,low,high):
# modified
pivot = arr[high]
i = low
j = high
while i < j:
#modified
while arr[i] >= pivot and i = low+1:
j -= 1
if i < j:
arr[i], arr[j] = arr[j], arr[i]
arr[low], arr[j] = arr[j],arr[low]
return j