350. Intersection of Two Arrays II

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

Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2].


  • 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?