Return Distinct Values Shared by Two Arrays

### Problem Return every value that appears in both nums1 and nums2, exactly once. The source accepts any output order. ```cpp vector<int> intersection(vector<int>& nums1, vector<int>& nums2); ``` ### Examples ```text nums1=[3,3,5,7], nums2=[7,3,7] -> [3,7] nums1=[1], nums2=[2] -> [] ``` ### Constraints - Each length is 1 through 1000. - Values lie in [0,1000]. ### Follow-up Questions Explain how the permitted output freedom is preserved without losing required values or occurrences. ### What a Strong Answer Covers Mark presence in the first array and clear a mark when it is emitted during a scan of the second. Explain why every produced result satisfies the source contract and why no required result is omitted.