78 lines
1.8 KiB
C++
78 lines
1.8 KiB
C++
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#include <iostream>
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using namespace std;
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int partition(int a[],int low,int high);
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void quickSort(int a[], int low, int high);
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// Driver Code
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int main()
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{
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cout<<"Enter the length of array"<<endl;
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int n;
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cin>>n;
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int *a = new int(n);
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// Getting elements of array
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cout<<"Enter the elements of array"<<endl;
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for (int i = 0; i < n; i++)
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cin>>a[i];
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cout << "Original array: \n";
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for (int i = 0; i < n; i++)
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cout << a[i] << " ";
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quickSort(a, 0, n - 1);
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cout << "\nSorted array: \n";
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for (int i = 0; i < n; i++)
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cout << a[i] << " ";
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delete (a);
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return 0;
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}
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// A utility function to swap two elements
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void swap(int *a, int *b)
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{
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int t = *a;
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*a = *b;
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*b = t;
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}
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/* This function takes last element as pivot, places
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the pivot element at its correct position in sorted
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aay, and places all smaller (smaller than pivot)
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to left of pivot and all greater elements to right
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of pivot */
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int partition(int a[], int low, int high)
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{
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int pivot = a[high];
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int i = (low - 1);
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for (int j = low; j <= high - 1; j++)
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{
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// If current element is smaller than the pivot
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if (a[j] < pivot)
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{
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i++; // increment index of smaller element
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swap(&a[i], &a[j]);
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}
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}
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swap(&a[i + 1], &a[high]);
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return (i + 1);
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}
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/* The main function that implements QuickSort
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a[] --> array to be sorted,
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low --> Starting index,
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high --> Ending index */
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void quickSort(int a[], int low, int high)
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{
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if (low < high)
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{
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/* pi is partitioning index, a[p] is now
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at right place */
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int pi = partition(a, low, high);
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// Separately sort elements before
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// partition and after partition
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quickSort(a, low, pi - 1);
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quickSort(a, pi + 1, high);
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}
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}
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