sort.c

#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int extraMemoryAllocated;

void swap(int* a, int* b)
{
 
    int temp = *a;
 
    *a = *b;
 
    *b = temp;
}
 
// To heapify a subtree rooted with node i
// which is an index in arr[].
// n is size of heap
void heapify(int arr[], int N, int i)
{
    // Find largest among root, left child and right child
 
    // Initialize largest as root
    int largest = i;
 
    // left = 2*i + 1
    int left = 2 * i + 1;
 
    // right = 2*i + 2
    int right = 2 * i + 2;
 
    // If left child is larger than root
    if (left < N && arr[left] > arr[largest])
 
        largest = left;
 
    // If right child is larger than largest
    // so far
    if (right < N && arr[right] > arr[largest])
 
        largest = right;
 
    // Swap and continue heapifying if root is not largest
    // If largest is not root
    if (largest != i) {
 
        swap(&arr[i], &arr[largest]);
 
        // Recursively heapify the affected
        // sub-tree
        heapify(arr, N, largest);
    }
}
 
// Main function to do heap sort
void heapSort(int arr[], int N)
{
 
    // Build max heap
    for (int i = N / 2 - 1; i >= 0; i--)
 
        heapify(arr, N, i);
 
    // Heap sort
    for (int i = N - 1; i >= 0; i--) {
 
        swap(&arr[0], &arr[i]);
 
        // Heapify root element to get highest element at
        // root again
        heapify(arr, i, 0);
    }
}

// implement merge sort
// extraMemoryAllocated counts bytes of extra memory allocated
void mergeSort(int pData[], int l, int r)
{
    if (l >= r) return;

    int mid = l + (r - l) / 2;
    mergeSort(pData, l, mid);
    mergeSort(pData, mid + 1, r);

    int n1 = mid - l + 1;
    int n2 = r - mid;

    int L[n1], R[n2];

    extraMemoryAllocated += sizeof(int) * (n1 + n2);

    for (int i = 0; i < n1; i++)
        L[i] = pData[l + i];
    for (int j = 0; j < n2; j++)
        R[j] = pData[mid + 1 + j];

    int i = 0, j = 0, k = l;

    while (i < n1 && j < n2) {
        if (L[i] <= R[j])
            pData[k++] = L[i++];
        else
            pData[k++] = R[j++];
    }

    while (i < n1) pData[k++] = L[i++];
    while (j < n2) pData[k++] = R[j++];
}


// parses input file to an integer array
int parseData(char *inputFileName, int **ppData)
{
	FILE* inFile = fopen(inputFileName,"r");
	int dataSz = 0;
	int i, n, *data;
	*ppData = NULL;
	
	if (inFile)
	{
		fscanf(inFile,"%d\n",&dataSz);
		*ppData = (int *)malloc(sizeof(int) * dataSz);
		// Implement parse data block
		if (*ppData == NULL)
		{
			printf("Cannot allocate memory\n");
			exit(-1);
		}
		for (i=0;i<dataSz;++i)
		{
			fscanf(inFile, "%d ",&n);
			data = *ppData + i;
			*data = n;
		}

		fclose(inFile);
	}
	
	return dataSz;
}

// prints first and last 100 items in the data array
void printArray(int pData[], int dataSz)
{
	int i, sz = dataSz - 100;
	printf("\tData:\n\t");
	for (i=0;i<100;++i)
	{
		printf("%d ",pData[i]);
	}
	printf("\n\t");
	
	for (i=sz;i<dataSz;++i)
	{
		printf("%d ",pData[i]);
	}
	printf("\n\n");
}

int main(void)
{
	clock_t start, end;
	int i;
    double cpu_time_used;
	char* fileNames[] = { "input1.txt", "input2.txt", "input3.txt", "input4.txt" };
	
	for (i=0;i<4;++i)
	{
		int *pDataSrc, *pDataCopy;
		int dataSz = parseData(fileNames[i], &pDataSrc);
		
		if (dataSz <= 0)
			continue;
		
		pDataCopy = (int *)malloc(sizeof(int)*dataSz);
	
		printf("---------------------------\n");
		printf("Dataset Size : %d\n",dataSz);
		printf("---------------------------\n");
		
		printf("Heap Sort:\n");
		memcpy(pDataCopy, pDataSrc, dataSz*sizeof(int));
		extraMemoryAllocated = 0;
		start = clock();
		heapSort(pDataCopy, dataSz);
		end = clock();
		cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
		printf("\truntime\t\t\t: %.1lf\n",cpu_time_used);
		printf("\textra memory allocated\t: %d\n",extraMemoryAllocated);
		printArray(pDataCopy, dataSz);
		
		printf("Merge Sort:\n");
		memcpy(pDataCopy, pDataSrc, dataSz*sizeof(int));
		extraMemoryAllocated = 0;
		start = clock();
		mergeSort(pDataCopy, 0, dataSz - 1);
		end = clock();
		cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
		printf("\truntime\t\t\t: %.1lf\n",cpu_time_used);
		printf("\textra memory allocated\t: %d\n",extraMemoryAllocated);
		printArray(pDataCopy, dataSz);
		
		free(pDataCopy);
		free(pDataSrc);
	}
	
}