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March 13, 2019 05:44
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Non randomized quicksort
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/* C implementation QuickSort */ | |
#include<stdio.h> | |
// A utility function to swap two elements | |
void swap(int* a, int* b) | |
{ | |
int t = *a; | |
*a = *b; | |
*b = t; | |
} | |
/* 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 */ | |
int partition (int arr[], int low, int high) | |
{ | |
int pivot = arr[high]; // pivot | |
int i = (low - 1); // Index of smaller element | |
for (int j = low; j <= high- 1; j++) | |
{ | |
// If current element is smaller than or | |
// equal to pivot | |
if (arr[j] <= pivot) | |
{ | |
i++; // increment index of smaller element | |
swap(&arr[i], &arr[j]); | |
} | |
} | |
swap(&arr[i + 1], &arr[high]); | |
return (i + 1); | |
} | |
/* The main function that implements QuickSort | |
arr[] --> Array to be sorted, | |
low --> Starting index, | |
high --> Ending index */ | |
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 */ | |
void printArray(int arr[], int size) | |
{ | |
int i; | |
for (i=0; i < size; i++) | |
printf("%d ", arr[i]); | |
printf("n"); | |
} | |
// Driver program to test above functions | |
int main() | |
{ | |
int arr[] = { 9, 5, 6, 3, 10, 4, 1, 2, 7, 8 }; | |
int n = sizeof(arr)/sizeof(arr[0]); | |
quickSort(arr, 0, n-1); | |
printf("Sorted array: n"); | |
printArray(arr, n); | |
return 0; | |
} |
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