merge_sort.c

#include <stdio.h> 
#include<time.h> 
int b[50000]; 
void Merge(int a[], int low, int mid, int high){ 
int i, j, k; 
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++] ; 
} 
while (i<=mid) 
b[k++] = a[i++] ; 
while (j<=high) 
b[k++] = a[j++] ; 
for(k=low; k<=high; k++) 
a[k] = b[k]; 
}
voidMergeSort(int a[], int low, int high){ 
int mid; 
if(low >= high) 
return; 
mid = (low+high)/2 ; 
MergeSort(a, low, mid); 
MergeSort(a, mid+1, high); 
Merge(a, low, mid, high); 
} 
void main(){ 
int n, a[50000],k; 
int clock_tst,et,doublets; 
printf("\n Enter How many Numbers:"); 
scanf("%d", &n); 
printf("\nThe Random Numbers are:\n"); 
for(k=1; k<=n; k++) { 
a[k]=rand(); 
printf("%d\t", a[k]); 
} 
int st=clock(); 
MergeSort(a, 1, n); 
et=clock(); 
int ts=(double)(et-st)/CLOCKS_PER_SEC; 
printf("\n Sorted Numbers are : \n "); 
for(k=1; k<=n; k++) 
printf("%d\t", a[k]); 
printf("\nThe time taken is %e",ts); 
}