Program 5 - Merge Sort

	#include <stdio.h>
	void merge(int a[], int f, int mid, int l){
	int i = f, j = mid + 1, k = 0, b[20];
	while(i <= mid && j <= l){
	if(a[i] <= a[j]){
	b[k++] = a[i++];
	} else if(a[i] > a[j]){
	b[k++] = a[j++];
	}
	}
	while(i <= mid){
	b[k++] = a[i++];
	}
	while(j <= l){
	b[k++] = a[l++];
	}
	for(i = f, k = 0; i <= l; i++, k++){
	a[i] = b[k];
	}
	}
	void merge_sort(int a[], int f, int l){
	int mid;
	if(f < l){
	mid = (f + l) / 2;
	merge_sort(a, f, mid);
	merge_sort(a, mid + 1, l);
	merge(a, f, mid, l);
	}
	}
	int main(){
	int i;
	//Worst Case xD
	int a[] = {4,3,2,1,0,-1,-2,-3,-4};
	int n = sizeof(a)/ sizeof(a[0]);
	merge_sort(a,0, n-1);
	printf("The sorted array is: \n");
	for(i = 0; i < n; i++){
	printf("%d ", a[i]);
	}
	return 0;
	}