MergeSort.c

#include<stdio.h>
#include<stdlib.h>
int count;
void mergesort(int [],int,int);
void merge(int [],int,int,int);
int main()
{
    int a[1200],b[1200],c[1200],n,i,c1,c2,c3,j;
    printf("ENTER THE NUMBER OF ELEMENTS\n");
    scanf("%d",&n);
    printf("ENTER ELEMENTS\n");
    for(i=0;i<n;i++)
    scanf("%d",&a[i]);
    mergesort(a,0,n-1);
    printf("SORTED ARRAY IS\n");
    for(i=0;i<n;i++)
    printf("%d ",a[i]);
    printf("\n");
    printf("TIME COMPLEXITY ANALYSIS\n");
    printf("SIZE\tASC\tDESC\tRANDOM\n");
    for(i=16;i<=1024;i=i*2)
    {
        for(j=0;j<i;j++)
        {
            a[j]=j;
            b[j]=i-j;
            c[j]=rand()%i+1;
        }
        count=0;
        mergesort(a,0,i-1);
        c1=count;
        count=0;
        mergesort(b,0,i-1);
        c2=count;
        count=0;
        mergesort(c,0,i-1);
        c3=count;
        printf("%d\t%d\t%d\t%d\n",i,c1,c2,c3);
    }
    return 0;
}
void mergesort(int a[],int low, int high)
{
    int mid;
    if(low<high)
    {
        mid=(low+high)/2;
        mergesort(a,low,mid);
        mergesort(a,mid+1,high);
        merge(a,low,mid,high);
    }
}
void merge(int a[],int low,int mid,int high)
{
    int b[1200],i=low,j=mid+1,k=low;
    while(i<=mid && j<=high)
    {
        if(a[i]<a[j])
        {
            b[k++]=a[i++];
        }
        else
        {
            b[k++]=a[j++];
        }
        count++;
    }
    while(i<=mid)
    {
        b[k++]=a[i++];
        count++;
    }
    while(j<=high)
    {
        b[k++]=a[j++];
        count++;
    }
    for(k=low;k<=high;k++)
    a[k]=b[k];
}