$2$A$)$ Create a class Compute with a method Sum$($String part$)$ which performs a summation of the array

elements. The part parameter specifies the summation of an array's first half or second half. Create

two child threads, where the first thread computes the summation of the first half, and the second

child performs the summation of the second half of an array of elements. The main thread

computes the total sum obtained from each child thread and displays it$.$ Write a multithreaded

program to perform the above operation. Assume a square matrix.

Note: If $n$ is the order of matrix, then $n\frac{2}{2}$ number of elements will be first half.

$2$B$)$ Given an integer array nums, return all the triplets $[$nums$[$i$],$ nums$[$i$],$ nums$[$k$]]$ such that $ij,ik,$

and $jl=k,$ and nums$[$i$]+$ nums$[$i$]+$ nums $[k]==0.$

Notice that the solution set must not contain duplicate triplets.

Example $1$:

Input: nums $=[-1,0,1,2,-1,-4]$

Output: $\left[\begin{array}{ccc}-1& -1& 2\\ -1& 0& 1\end{array}\right]$

Explanation:

nums $[0]+$ nums$[1]+$ nums$[2]=(-1)+0+1=0.$

nums$[1]+$ nums$[2]+$ nums$[4]=0+1+(-1)=0.$

nums $[0]+$ nums$[3]+$ nums$[4]=(-1)+2+(-1)=0.$

The distinct triplets are $-1,0,1$ and $-1,-1,2.$

Notice that the order of the output and the order of the triplets does not matter.

Example $2$:

Input: nums $=[0,1,1]$

Output: $[]$

Explanation: The only possible triplet does not sum up to $0.$

Example $3$:

Input: nums $=[0,0,0]$

Output: $\left[\begin{array}{ccc}0& 0& 0\end{array}\right]$

Explanation: The only possible triplet sums up to $0.$