Sorting • Your task is to design and implement a sorting algorithm that can sort
ID: 3885055 • Letter: S
Question
Sorting
• Your task is to design and implement a sorting algorithm that can sort integers that are less than or equal to L and greater than or equal to –L.
• You will have a large array of numbers, of size N e.g. N=10,000, L=30: you have 10,000 numbers to sort, but the numbers are only from [-30...30] range
• You should design an algorithm that works in O(N+L) time, that is, running time grows as a linear function of the array size, as long as L is not changed • Hint: Use one of the Majority Element algorithms for inspiration in your thinking about the algorithm
Input-output formats
• Take integers from standard input (System.in): – Line 1: single integer specifying N, number of elements in array (1<=N<=100,000) – Line 2: single integer specifying L, limit on the absolute value of the integers in the array (1<=L<=100) – Lines 3 to N+2: integers to be sorted, each in range [-L, L].
• Print sorted array to standard output (System.out), with each integer on a separate line • As always, do not print any text or blank lines to standard output except the integers
• As always, do not print any text or blank lines to standard output except the integers
Explanation / Answer
/* 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[] = {10, 7, 8, 9, 1, 5};
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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