Created QuickSort.cpp

C++/QuickSort.cpp

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+/*Quicksort Complexity
+
+Time Complexity	 
+Best 	        O(n*log n)
+Worst	        O(n2)
+Average   	O(n*log n)
+
+Space Complexity	O(n)
+*/
+
+
+#include<iostream>
+using namespace std;
+
+
+int partition( int arr[], int s, int e) {
+
+    int pivot = arr[s];
+
+    int cnt = 0;
+    for(int i = s+1; i<=e; i++) {
+        if(arr[i] <=pivot) {
+            cnt++;
+        }
+    }
+
+    //place pivot at right position
+    int pivotIndex = s + cnt;
+    swap(arr[pivotIndex], arr[s]);
+
+    //sorting left and right part of the pivot element
+    int i = s, j = e;
+
+    while(i < pivotIndex && j > pivotIndex) {
+
+        while(arr[i] <= pivot) 
+        {
+            i++;
+        }
+
+        while(arr[j] > pivot) {
+            j--;
+        }
+
+        if(i < pivotIndex && j > pivotIndex) {
+            swap(arr[i++], arr[j--]);
+        }
+
+    }
+
+    return pivotIndex;
+
+}
+
+void quickSort(int arr[], int s, int e) {
+
+    //base case
+    if(s >= e) 
+        return ;
+
+    //performing partition 
+    int p = partition(arr, s, e);
+
+    //sort the left part 
+    quickSort(arr, s, p-1);
+
+    //sort right part 
+    quickSort(arr, p+1, e);
+
+}
+
+int main() {
+
+    int arr[5] = {5,4,9,6,2};
+    int n = 5;
+
+    quickSort(arr, 0, n-1);
+
+    for(int i=0; i<n; i++) 
+    {
+        cout << arr[i] << " ";
+    }
+    cout << endl;
+
+
+    return 0;
+}