Notes

Veeresh Shukla
6:06 PM (5 minutes ago)
to me

#include <stdio.h>
#include <stdlib.h>
#include<time.h>
void merge(int arr[], int l, int m, int r)
{
int i, j, k;
int n1 = m - l + 1;
int n2 = r - m;

int L[n1], R[n2];

for (i = 0; i < n1; i++)
L[i] = arr[l + i];
for (j = 0; j < n2; j++)
R[j] = arr[m + 1 + j];


i = 0;
j = 0;
k = l;
while (i < n1 && j < n2) {
if (L[i] <= R[j]) {
arr[k] = L[i];
i++;
}
else {
arr[k] = R[j];
j++;
}
k++;
}

while (i < n1) {
arr[k] = L[i];
i++;
k++;
}


while (j < n2) {
arr[k] = R[j];
j++;
k++;
}
}

void mergeSort(int arr[], int l, int r)
{
if (l < r) {
int m = l + (r - l) / 2;
mergeSort(arr, l, m);
mergeSort(arr, m + 1, r);

merge(arr, l, m, r);
}
}
void printArray(int A[], int size)
{
int i;
for (i = 0; i < size; i++)
printf("%d ", A[i]);
printf("n");
}
int main()
{ int n;
int choice;
int arr1[] ={1,2,3,4,5,6,7,8};
int arr2[]={8,7,6,5,4,3,2,1};
int *arr;
int arr_size=8;
int x;
printf("Enter choice n 1.for random n 2.for sorted n3.for reversely sorted");
scanf("n %d",&choice);
switch(choice)
{
case 2:
{arr=arr1;
break;}
case 3:
{arr=arr2;
break;}
case 1:
{printf("Enter the size of the array");
scanf("n%d",&n);
int arr3[n];
arr=arr3;
for(int i=0;i<n;i++)
arr[i]=rand()%200;
arr_size=n;
break;
}}

clock_t start_t, end_t, total_t;

printf("Given array is n");
printArray(arr, arr_size);
start_t=clock();
mergeSort(arr, 0, arr_size - 1);
end_t=clock();
total_t=(double)(end_t - start_t);
printf("nSorted array is n");
printArray(arr, arr_size);
printf("Time in ms is %ld",total_t);
printf("%d",rand()%50);
return 0;
}