2215 Find the Difference of Two Arrays 1

Joel Castillo Espinosa 2

DESCRIPTION

Given two 0-indexed integer arrays nums1 and nums2, return a list answer of size 2 where:

  • answer[0] is a list of all distinct integers in nums1 which are not present in nums2.
  • answer[1] is a list of all distinct integers in nums2 which are not present in nums1.

Note that the integers in the lists may be returned in any order.

Examples

  • Example 1:
    • Input: nums1 = [1,2,3], nums2 = [2,4,6]
    • Output: [[1,3],[4,6]]
    • Explanation: For nums1, nums1[1] = 2 is present at index 0 of nums2, whereas nums1[0] = 1 and nums1[2] = 3 are not present in nums2. Therefore, answer[0] = [1,3]. For nums2, nums2[0] = 2 is present at index 1 of nums1, whereas nums2[1] = 4 and nums2[2] = 6 are not present in nums1. Therefore, answer[1] = [4,6].
  • Example 2:
    • Input: nums1 = [1,2,3,3], nums2 = [1,1,2,2]
    • Output: [[3],[]]
    • Explanation: For nums1, nums1[2] and nums1[3] are not present in nums2. Since nums1[2] == nums1[3], their value is only included once and answer[0] = [3].Every integer in nums2 is present in nums1. Therefore, answer[1] = [].

Constraints:

  • 1 ≤ nums1.length,nums2.length ≤ 1000
  • -1000 ≤ nums1[i],nums2[i] ≤ 1000

SOLUTION 3

dif_array <- function(nums1, nums2){
  nums1r <- nums1
  nums2r <- nums2
  
  # in each iteration, check if nums1[i] matches in nums2
    # then drop the matches or keep in both arrays 
  for (i  in nums1) {
    match <- sum(nums2r == i)
    if(match > 0){
    nums2r <- nums2r[nums2r != i] # drop matches in nums2
    nums1r <- nums1r[nums1r != i] # drop matches in nums1
    }
  }
  
  # for empty arrays (if it is necessary)
  if(length(nums1r) == 0 ) {
    nums1r <- " "  } 
  if(length(nums2r) == 0 ) {
    nums2r <- " "  }
  
  return(list(unique(nums1r), unique(nums2r)))
}

Examples using the function

We can use the examples presented before.

dif_array(c(1,2,3), c(2,4,6))

## [[1]]
## [1] 1 3
## 
## [[2]]
## [1] 4 6

dif_array(c(1,2,3,3), c(1,1,2,2))

## [[1]]
## [1] 3
## 
## [[2]]
## [1] " "

  1. This problem is originally from LeetCode, you can find it in Leetcode. ↩

  2. Email: jocastillo@colmex.mx. For more content visit my website: https://joelcastillo.netlify.app
    If you have any questions or suggestions, I’d be grateful to hear from you. ↩

  3. This solution is entirely my own work. It was developed using R version 4.4.1 (2024-06-14 ucrt). ↩