Solution: Find Two Pairs in an Array Such That a+b = c+d
Let’s solve the Find Two Pairs in an Array Such That a+b = c+d problem.
We'll cover the following
Statement
Given an array of distinct integers, nums
, determine whether there exist two pairs,
Constraints:
nums.length
nums[i]
Solution
In this solution, we identify pairs of numbers with matching sums by utilizing a map to remember the sums and its associated pairs. By storing each unique sum as a key and the corresponding pair as its value, the algorithm can quickly check if a previously encountered sum matches the sum of a current pair. This enables the identification of two distinct pairs that add up to the same sum.
Let’s walk through the following steps of the solution:
Initializes an empty
map
to store the sum of pairs.Iterate over each pair of numbers in
nums
and calculate theirsum
. Check whether thissum
has already been encountered and stored in themap
:If yes, return the two pairs that add up to this
sum
: the one previously stored and the current one.Otherwise, add the
sum
as key and its pair as the corresponding value in themap
for future reference.
Return NULL, if no such pairs are found by the end of the iteration.
Let’s look at the illustration below to better understand the solution:
Level up your interview prep. Join Educative to access 80+ hands-on prep courses.