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Two sets of ‘n’ numbers are given A and B. Chose one element from A and one from B such that the sum is equal to a given value, ‘val’.
I have got the solution as:
We can hash the elements of Set A and Set B and check for every element in set A whether val-arr[i] exists in the hash of Set B or not. This would take O(n) time and O(n) space
Can there be a better solutions with space as O(1) and time O(n)?
As you have both the arrays NOT sorted, you have NO other option but look at every element one-by-one. So, you cannot get below
O(n)running time. I think the approach you are using is ok.Read these related posts:
Given two arrays a and b .Find all pairs of elements (a1,b1) such that a1 belongs to Array A and b1 belongs to Array B whose sum a1+b1 = k
Find two elements in an array that sum to k