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Coding/Arrays and strings

First unique scan

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Your task

A returns desk scans package IDs as they arrive; an ID showing up more than once means a duplicate label. Given the scan log in order, return the first ID that appears exactly once in the whole log, or -1 if every ID repeats (or the log is empty). Example: [2, 3, 2, 4, 3] returns 4.

Examples

first_unique_scan(ids: list[int]) -> int
Example 1
Inputfirst_unique_scan([2, 3, 2, 4, 3])
Output4