From 88327f348cc809017bf329ed99a4c8d4c107bdf9 Mon Sep 17 00:00:00 2001
From: ANSH GUPTA <68772910+PROFESSORRQ@users.noreply.github.com>
Date: Wed, 12 Aug 2020 15:51:55 +0530
Subject: [PATCH] updated quick sort algorithm

Its a c++ program for quick sort
---
 quicksort.c   | 48 -----------------------------------------------
 quicksort.cpp | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 48 deletions(-)
 delete mode 100644 quicksort.c
 create mode 100644 quicksort.cpp

diff --git a/quicksort.c b/quicksort.c
deleted file mode 100644
index 116a852..0000000
--- a/quicksort.c
+++ /dev/null
@@ -1,48 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-int quicksort(int*a, int len){
-    quicksort_r(a,0,len-1);
-    return 0;
-}
-int quicksort_r(int* a,int start,int end){
-    if (start>=end) {
-        return 0;
-    }
-    int pivot=a[end];
-    int swp;
-    //set a pointer to divide array into two parts
-    //one part is smaller than pivot and another larger
-    int pointer=start;
-    int i;
-    for (i=start; i<end; i++) {
-        if (a[i]<pivot) {
-            if (pointer!=i) {
-                //swap a[i] with a[pointer]
-                //a[pointer] behind larger than pivot
-                swp=a[i];
-                a[i]=a[pointer];
-                a[pointer]=swp;
-            }
-            pointer++;
-        }
-    }
-    //swap back pivot to proper position
-    swp=a[end];
-    a[end]=a[pointer];
-    a[pointer]=swp;
-    quicksort_r(a,start,pointer-1);
-    quicksort_r(a,pointer+1,end);
-    return 0;
-}
-
-int main(){
-    int a[10]={2,1,4,7,5,8,9,20,0,3};
-    int len=10;
-    quicksort(a,len);
-    int i;
-    for (i=0; i<len; i++) {
-        printf("%d\t",a[i]);
-    }
-    printf("\n");
-    return 0;
-}
\ No newline at end of file
diff --git a/quicksort.cpp b/quicksort.cpp
new file mode 100644
index 0000000..d1b7e2a
--- /dev/null
+++ b/quicksort.cpp
@@ -0,0 +1,52 @@
+#include<bits/stdc++.h>
+using namespace std;
+int partition(int A[],int lb,int ub)
+{
+ int pivot=A[lb];
+ int start=lb;
+ int end=lb+1;
+ while(end<=ub)
+ {
+     if(A[end]>pivot)
+     {
+     end++;
+     start++;
+     }
+     
+     if(pivot>A[end])
+     {
+         int temp=A[start];
+         A[start]=A[end];
+         A[end]=temp;
+         start++;
+         end++;
+     }
+
+ }
+return start;
+}
+void quicksort(int A[],int lb,int ub)
+{
+    if(lb<ub){
+    int loc=partition(A,lb,ub);
+    quicksort(A,lb,loc-1);
+    quicksort(A,loc+1,ub);
+    }
+}
+int main()
+{
+    int n;
+    cin>>n;
+    int A[n];
+    int lb=0;int ub=n-1;
+    for(int i=0;i<n;i++)
+    {
+        cin>>A[i];
+    }
+    quicksort(A,lb,ub);
+    for(int i=0;i<n;i++)
+    {
+        cout<<A[i]<<" ";
+    }
+
+}