Python List Comprehension to find pair with given sum from two arrays

Given two unsorted arrays of distinct elements, the task is to find all pairs from both arrays whose sum is equal to x. 

Examples:

Input :  arr1 = [-1, -2, 4, -6, 5, 7]
         arr2 = [6, 3, 4, 0]  
         x = 8
Output : [(5, 3), (4, 4)]
         
Input : arr1 = [1, 2, 4, 5, 7] 
        arr2 = [5, 6, 3, 4, 8]  
        x = 9
Output : [(1, 8), (4, 5), (5, 4)]

We have existing solution for this problem please refer Given two unsorted arrays, find all pairs whose sum is x link. We can solve this problem quickly in python using List comprehension. Approach is very simple, we will consider all those pairs for which if k lies in arr2 then x-k should lie in arr1, so pair will be (x-k,k). 

Implementation:

# Function to find all pairs whose sum is x in
# two arrays
def allPairs(arr1,arr2,x):
    
    # finds all pairs in two arrays
    # whose sum is x
    print ([(x-k,k) for k in arr2 if (x-k) in arr1])
# Driver program
if __name__ == "__main__":
    arr1 = [-1, -2, 4, -6, 5, 7]
    arr2 = [6, 3, 4, 0]
    x = 8
    allPairs(arr1,arr2,x)

[(5, 3), (4, 4)]

Complexity : O(n*n)