leetcode

commit 6ef5b6f9f1f65991b90ee770efb0cf356998821d
parent 90793ee4ccd515d2d80aa9453202ddd58023c962
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Wed,  3 May 2023 08:39:29 -0500

Completed difference of arrays using hashmap

Diffstat:
A
find-the-difference-of-two-array/difference-of-two-arrays.dart
 | 
29
+++++++++++++++++++++++++++++

1 file changed, 29 insertions(+), 0 deletions(-)
diff --git a/find-the-difference-of-two-array/difference-of-two-arrays.dart b/find-the-difference-of-two-array/difference-of-two-arrays.dart
@@ -0,0 +1,29 @@
+//Find all unique values that appear in one list but not the other
+//then return the unique values as two lists.
+//I used a hashmap for this when I should have used a set because 
+//I only need to know unique values and not how many of each there are.
+//The time complexity of this code is O(n + k) where n is the number of elements
+//in the first list and k is the number in the second. 
+//Time: 375ms Beats: 30%
+//Memory: 150.5MB Beats: 60%
+
+class Solution {
+  List<List<int>> findDifference(List<int> nums1, List<int> nums2) {
+      Map<int , int> map1 = {};
+      Map <int, int> map2 = {};
+      for(int i = 0 ; i < nums1.length ; ++i){
+          map1[nums1[i]] = (map1[nums1[i]] ?? 0) + 1;
+      }
+      for(int i = 0 ; i < nums2.length ; ++i){
+          map2[nums2[i]] = 1;
+      }
+      for(int i = 0 ; i < nums1.length ; ++i){
+          map2.remove(nums1[i]);
+      }
+      for(int i = 0 ; i < nums2.length ; ++i){
+          map1.remove(nums2[i]);
+      }
+      
+      return [map1.keys.toList() , map2.keys.toList()];
+  }
+}