Find Anagram Mapping

Given two lists A and B, and B is an anagram of A. B is an anagram of A means B is made by randomizing the order of the elements in A.

We want to find an index mapping P, from A to B. A mapping P[i] = j means the ith element in A appears in B at index j.

These lists A and B may contain duplicates. If there are multiple answers, output any of them.

Example Given A = [12, 28, 46, 32, 50] and B = [50, 12, 32, 46, 28], return [1, 4, 3, 2, 0].

Explanation: as P[0] = 1 because the 0th element of A appears at B[1], and P[1] = 4 because the 1st element of A appears at B[4], and so on.

Solution: Hash table

    vector<int> anagramMappings(vector<int>& A, vector<int>& B) {
        vector<int> res;
        unordered_map<int, int> m;
        for (int i = 0; i < B.size(); ++i) m[B[i]] = i;
        for (int num : A) res.push_back(m[num]);
        return res;
    }