# Intersection of Two Arrays II Problem

0 like 0 dislike
3.1k views

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.

• 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?

0 like 0 dislike
by Goeduhub's Expert (2.3k points)

Simple count all the occurance of each number for nums 1 and then compare its freq from nums 2 to get final ans.

class Solution:

def intersect(self, nums1: List[int], nums2: List[int]) -> List[int]:

dict1 = dict()

for i in nums1:

if i not in dict1:

dict1[i] = 1

else:

dict1[i] += 1

ret = []

for i in nums2:

if i in dict1 and dict1[i]>0:

ret.append(i)

dict1[i] -= 1

return ret

eg : ans = Solution()

nums1 = [1,2,2,1], nums2 = [2,2]

ans.intersect(nums1, nums2)

Output -

[2,2]

Learn & Improve In-Demand Data Skills Online in this Summer With  These High Quality Courses[Recommended by GOEDUHUB]:-

Best Data Science Online Courses[Lists] on:-

Claim your 10 Days FREE Trial for Pluralsight.