LeetCode 1122 Relative Sort Array [sort] java

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Given two arrays arr1 and arr2, the elements of arr2 are distinct, and all elements in arr2 are also in arr1.

Sort the elements of arr1 such that the relative ordering of items in arr1 are the same as in arr2.  Elements that don’t appear in arr2should be placed at the end of arr1 in ascending order.

Example 1:

Input: arr1 = [2,3,1,3,2,4,6,7,9,2,19], arr2 = [2,1,4,3,9,6]
Output: [2,2,2,1,4,3,3,9,6,7,19]


  • arr1.length, arr2.length <= 1000
  • 0 <= arr1[i], arr2[i] <= 1000
  • Each arr2[i] is distinct.
  • Each arr2[i] is in arr1.

First, we put all elements from arr2 into a hashmap. Then we count every element in arr1, if it is in arr2, we count it, else we put it to others. Then we output numbers from hashmap and others.

Running time is 2 ms faster than 73.13% Java submissions.

Github address:

To find other sort problems, see also Sort algorithms and problems.

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