• Sort the given array.
• Then use the left and right pointers.
• Calculate the sum of the left and right element of array.
• Check if the sum is less then absolute value of previous sum
• Update the previous sum.
• If sum is less than zero the increase left pointer by one.
• Otherwise,decrease right point by one.

Python Code

test=int(input())
for i in range(test):
    size=int(input())
    arr=list(map(int,input().split()))
    left=0
    right=size-1
    sum,minsum=0,10**9
    arr.sort()
    while(left< right):
        sum=arr[left]+arr[right]
        if(abs(sum)< abs(minsum)):
            minsum=sum
        if(sum< 0):
            left+=1
        else:
            right-=1
    print(minsum)