Sorting-Merge_sort.cpp

#include<bits/stdc++.h>
using namespace std;
void merge(int *a,int *l,int left,int *r,int right) {
	int i=0,j=0,k=0;
	
	while(i<left && j< right) {
		if(l[i]  < r[j]) 
		  a[k++] = l[i++];
		else a[k++] = r[j++];
	}
	while(i < left)
	    a[k++] = l[i++];
	while(j < right) 
	   a[k++] = r[j++];
}
void merge_sort(int *a,int n)
{
    int mid,*l,*r,i;
    if(n<2)
    return ;
    
    mid=n/2;
    l=new int[mid];
    
    r=new int[n-mid];

    for(i=0;i<mid;i++)
    l[i]=a[i];
    for(i=mid;i<n;i++)
    r[i-mid]=a[i];
   
    merge_sort(l,mid);
    merge_sort(r,n-mid);
    merge(a,l,mid,r,n-mid);
}
int main()
{
    int n;
    cout<<"Size of Array::";
    cin>>n;
    int a[n];
    cout<<"Enter Sequence::";
    for(int i=0;i<n;i++)
    cin>>a[i];
   
    //merge short
    merge_sort(a,n);
    cout<<"Sorted Array::";
    for(int i=0;i<n;i++)cout<<a[i]<<" ";
    //6 2 3 1 9 10 15 13 12 17
}