350. Intersection of Two Arrays II

Given two arrays, write a function to compute their intersection.

Example 1:

Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2,2]

Example 2:

Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [4,9]

Note:

• Each element in the result should appear as many times as it shows in both arrays.

• The result can be in any order.

Follow up:

• What if the given array is already sorted? How would you optimize your algorithm?

• What if nums1's size is small compared to nums2's size? Which algorithm is better?

• What if elements of nums2 are stored on disk, and the memory is limited such that you cannot load all elements into the memory at once?

# @param {Integer[]} nums1
# @param {Integer[]} nums2
# @return {Integer[]}
def intersect(nums1, nums2)
  arr = []
  nums1.sort.uniq.map{|k| arr += Array.new([nums1.count(k),nums2.count(k)].min,k) if nums2.include?(k)}
  arr
end