Write a c++ program that can sort an array of ten integers using merge sort. Divide the array into three parts instead of two and recursively sort each third and merge them. Solution #include <iostream> using namespace std; #include <conio.h> void MERGE(int , int , int , int ); void 3_mergesort(int A[20], int k, int l) { if(k<l) { int one_third = (l-k)/3; int two_third = 2*(l-k)/3; // k < k+one_third < k+two_third < l 3_mergesort(A,k,k+one_third); 3_mergesort(A,k+one_third+1,k+two_third); 3_mergesort(A,k+two_third+1,l); MERGE(A,k,k+one_third,k+two_third); MERGE(A,k,k+two_third,l); } } void MERGE(int A[20], int p, int q, int r) { int i = p; int j = q+1; int lenght = r - p + 1; int k=0; int merged[20]; merged.assign (lenght,0); while((i<=q)&&(j<=r)) { if(A[i] <= A[j]) { merged[k]=A[i]; ++i; } else { merged[k]=A[j]; ++j; } k++; } if(j<=r) { while(j<=r) { merged[k]=A[j]; ++j; ++k; } } if(i<=q) { while(i<=q) { merged[k]=A[i]; ++i; ++k; } } for (i=0;i<lenght;++i) A[p+i]=merged[i]; } int main() { int a[20],i; cout<<\"enter the elements\ \"; for (i = 0; i < 5; i++) { cin>>a[i]; } 3_mergesort(a, 0, 4); cout<<\"sorted array\ \"; for (i = 0; i < 5; i++) { cout<<a[i]; } getch(); } .

1. Write a c++ program that can sort an array of ten integers using merge sort. Divide the array into
three parts instead of two and recursively sort each third and merge them.
Solution
#include <iostream>
using namespace std;
#include <conio.h>
void MERGE(int , int , int , int );
void 3_mergesort(int A[20], int k, int l)
{
if(k<l)
{
int one_third = (l-k)/3;
int two_third = 2*(l-k)/3; // k < k+one_third < k+two_third < l
3_mergesort(A,k,k+one_third);
3_mergesort(A,k+one_third+1,k+two_third);
3_mergesort(A,k+two_third+1,l);
MERGE(A,k,k+one_third,k+two_third);
MERGE(A,k,k+two_third,l);
}
}
void MERGE(int A[20], int p, int q, int r)
{
int i = p;
int j = q+1;
int lenght = r - p + 1;
int k=0;
int merged[20];
merged.assign (lenght,0);
while((i<=q)&&(j<=r))
{
if(A[i] <= A[j])
{
merged[k]=A[i];
++i;

2. }
else
{
merged[k]=A[j];
++j;
}
k++;
}
if(j<=r)
{
while(j<=r)
{
merged[k]=A[j];
++j;
++k;
}
}
if(i<=q)
{
while(i<=q)
{
merged[k]=A[i];
++i;
++k;
}
}
for (i=0;i<lenght;++i)
A[p+i]=merged[i];
}
int main()
{
int a[20],i;
cout<<"enter the elements ";
for (i = 0; i < 5; i++)
{
cin>>a[i];
}
3_mergesort(a, 0, 4);
cout<<"sorted array ";
for (i = 0; i < 5; i++)
{
cout<<a[i];
}

3. getch();
}