FindAnagramMappings.js

// Source : https://leetcode.com/problems/find-anagram-mappings
// Author : Dean Shi
// Date   : 2018-01-14

/***************************************************************************************
 * 
 * Given two lists Aand 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.
 * 
 * For example, given
 * A = [12, 28, 46, 32, 50]
 * B = [50, 12, 32, 46, 28]
 * 
 * We should return
 * [1, 4, 3, 2, 0]
 * 
 * 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.
 * 
 * Note:
 * A, B have equal lengths in range [1, 100].
 * A[i], B[i] are integers in range [0, 10^5].
 * 
 ***************************************************************************************/

/**
 * @param {number[]} A
 * @param {number[]} B
 * @return {number[]}
 */
var anagramMappings = function(A, B) {
    const map = new Map()
    B.forEach((n, i) => map.set(n, i))

    return A.map(n => map.get(n))
};