count frequency of each sum obtained from the pairs of arr1 [ ] and arr2 [ ] and store them in 'um
for i in range ( n ) : NEW_LINE INDENT for j in range ( n ) : NEW_LINE INDENT if ( arr1 [ i ] + arr2 [ j ] ) in m : NEW_LINE INDENT m [ arr1 [ i ] + arr2 [ j ] ] += 1 NEW_LINE DEDENT else : NEW_LINE INDENT m [ arr1 [ i ] + arr2 [ j ] ] = 1 NEW_LINE DEDENT DEDENT DEDENT