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May 6, 2021 18:58
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Java implementation of QuickSort
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// Java implementation of QuickSort | |
import java.io.*; | |
class GFG{ | |
// A utility function to swap two elements | |
static void swap(int[] arr, int i, int j) | |
{ | |
int temp = arr[i]; | |
arr[i] = arr[j]; | |
arr[j] = temp; | |
} | |
/* This function takes last element as pivot, places | |
the pivot element at its correct position in sorted | |
array, and places all smaller (smaller than pivot) | |
to left of pivot and all greater elements to right | |
of pivot */ | |
static int partition(int[] arr, int low, int high) | |
{ | |
// pivot | |
int pivot = arr[high]; | |
// Index of smaller element and | |
// indicates the right position | |
// of pivot found so far | |
int i = (low - 1); | |
for(int j = low; j <= high - 1; j++) | |
{ | |
// If current element is smaller | |
// than the pivot | |
if (arr[j] < pivot) | |
{ | |
// Increment index of | |
// smaller element | |
i++; | |
swap(arr, i, j); | |
} | |
} | |
swap(arr, i + 1, high); | |
return (i + 1); | |
} | |
/* The main function that implements QuickSort | |
arr[] --> Array to be sorted, | |
low --> Starting index, | |
high --> Ending index | |
*/ | |
static void quickSort(int[] arr, int low, int high) | |
{ | |
if (low < high) | |
{ | |
// pi is partitioning index, arr[p] | |
// is now at right place | |
int pi = partition(arr, low, high); | |
// Separately sort elements before | |
// partition and after partition | |
quickSort(arr, low, pi - 1); | |
quickSort(arr, pi + 1, high); | |
} | |
} | |
// Function to print an array | |
static void printArray(int[] arr, int size) | |
{ | |
for(int i = 0; i < size; i++) | |
System.out.print(arr[i] + " "); | |
System.out.println(); | |
} | |
// Driver Code | |
public static void main(String[] args) | |
{ | |
int[] arr = { 10, 7, 8, 9, 1, 5 }; | |
int n = arr.length; | |
quickSort(arr, 0, n - 1); | |
System.out.println("Sorted array: "); | |
printArray(arr, n); | |
} | |
} |
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