Quick Sort | Code and Explanation | C++ Course – 19.2 | Nội Dung về chủ đề quick sort c++ |

Explain this topic in long video .
It is complicated one .

#include <iostream>

using namespace std;

void swap(int arr[], int i, int j){

int temp = arr[i];

arr[i] = arr[j];

arr[j] = temp;

}

int partition(int arr[], int l, int r){

int pivot = arr[r];

int i = l-1;

for(int j=l; j<r;i++){

if(arr[i]<pivot){

i++;

swap(arr,i,j);

}

swap(arr,i+1,r);

return i+1;

}

}

void quicksort(int arr[],int l,int r){

if(l<r){

int pi = partition(arr,l,r);

quicksort(arr,l,pi-1);

quicksort(arr,pi+1,r);

}

}

int main()

{

int n;

cin >> n;

int arr[n];

for (int i = 0; i <n;i++){

cin >> arr[i];

}

quicksort(arr,0,n-1);

for (int i = 0; i<n;i++){

cout << arr[i] << " ";

}

cout << endl;

return 0;

}

Why does this code return "4 6 5 3 2 1" instead of "1 2 3 4 5 6"?
Someone please help

Why you took i=L-1;
Then swapped i+1;
Why not take only i;
🙂🙂

prog.cpp: In function ‘int partition(int, int, int)’:

prog.cpp:10:22: error: invalid types ‘int[int]’ for array subscrip yeh wala error aa raha when i am running it

Very good explanation

Quick_short function my error btataa h (pi-1) kye pss😓😓😓😓😓

when I pass array is it pass by reference??

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It is giving wrong output
n is also not defined
I am getting output as 14523

In lecture we were told that its our choice to choose pivot i guess
Amd if thats the case then why don't we always choose median element as pivot ?

anuj bhaiya was better

Pls teach in easy way