Given integer lists a and b, return the values that appear in exactly one of the two lists. Output first the qualifying values from a (in order of first appearance in a), then the qualifying values from b (in order of first appearance in b). Each value appears once.
Examples
Input: a = [1, 2, 2, 3], b = [3, 4, 1, 4]
Output: [2, 4]
Input: a = [5, 6], b = [7, 5]
Output: [6, 7]
Constraints
0 <= len(a), len(b) <= 10**5- Target complexity: O(n + m) time.
Goals
- Combine two set differences
- Follow a two-part ordering rule