Is Find Anagram Mappings easy or hard?

Find Anagram Mappings is classified as an Easy problem. The main concept is recognizing that repeated searches can be replaced with a hash map to achieve linear time.

Find Anagram Mappings Python/Java solution

The typical implementation builds a dictionary or HashMap from nums2 values to indices. Then a second loop over nums1 fills the result array using map lookups. The same logic works in Python, Java, C++, Go, and TypeScript with standard hash map structures.

How to solve Find Anagram Mappings in O(n)?

First build a hash map that stores the indices of every value in nums2. Then iterate through nums1 and look up the corresponding index for each value in the map. If duplicates exist, store lists of indices and pop one when used. Both passes together produce an O(n) solution.

What is the best approach for Find Anagram Mappings?

The best approach uses a hash table to map values in nums2 to their indices. After building the map in one pass, iterate through nums1 and retrieve each index using constant-time lookups. This reduces the complexity to O(n) time with O(n) extra space.

Is Find Anagram Mappings asked at Google/Amazon/Meta?

Find Anagram Mappings is an easy-level interview problem that tests hash table fundamentals and array indexing. Variations of index mapping and hash-based lookups appear frequently in interviews at companies like Amazon and Google.

What data structure is used in Find Anagram Mappings?

A hash table (hash map) is the key data structure. It stores value-to-index mappings from nums2 so that each lookup for nums1 can be done in constant time.

What is the time complexity of Find Anagram Mappings?

The optimal hash table solution runs in O(n) time because each array is traversed once and hash lookups take O(1) on average. The brute force alternative requires O(n²) time since it scans nums2 for every element in nums1.

Description Hints 1 Solution Video 5:21

760. Find Anagram Mappings

Easy83.8% acceptance1 companyPremium elsewhere, free here

You are given two integer arrays nums1 and nums2 where nums2 is an anagram of nums1. Both arrays may contain duplicates.

Return an index mapping array mapping from nums1 to nums2 where mapping[i] = j means the i^th element in nums1 appears in nums2 at index j. If there are multiple answers, return any of them.

An array a is an anagram of an array b means b is made by randomizing the order of the elements in a.

Example 1:

Input: nums1 = [12,28,46,32,50], nums2 = [50,12,32,46,28]
Output: [1,4,3,2,0]
Explanation: As mapping[0] = 1 because the 0^th element of nums1 appears at nums2[1], and mapping[1] = 4 because the 1^st element of nums1 appears at nums2[4], and so on.

Example 2:

Input: nums1 = [84,46], nums2 = [84,46]
Output: [0,1]

Constraints:

1 <= nums1.length <= 100
nums2.length == nums1.length
0 <= nums1[i], nums2[i] <= 10⁵
nums2 is an anagram of nums1.

Asked at 1 company

Google

Topics

Array Hash Table

Hints open one at a time

Hint 1

Create a hashmap so that D[x] = i whenever B[i] = x. Then, the answer is [D[x] for x in A].

5:21

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  def solve(self):
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Starter codePython 3Spaces: 4

Examples

Case 1Case 2

Input

[12,28,46,32,50]
[50,12,32,46,28]

Input

[84,46]
[84,46]

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