[LintCode] Problem 813 - Find Anagram Mappings

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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.

Note

  • A, B have equal lengths in range [1, 100].
  • A[i], B[i] are integers in range [0, 10^5].

Example

No.1

Input: A = [12, 28, 46, 32, 50] and B = [50, 12, 32, 46, 28]

Output: [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.

No.2

Input: A = [1, 2, 3, 4, 5] and B = [5, 4, 3, 2, 1]

Output: [4, 3, 2, 1, 0]

Explanation:
As P[0] = 4 because the 0th element of A appears at B[4], and P[1] = 3 because the 1st element of A

Code

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public int[] anagramMappings(int[] A, int[] B) {
    int[] result = new int[A.length];
    Map<Integer, Integer> map = new HashMap<>();

    for (int i = 0; i < B.length; i++)
        map.put(B[i], i);

    for (int i = 0; i < A.length; i++)
        result[i] = map.get(A[i]);

    return result;
}