Sort an Array According to Another Array in Java

Given two arrays of equal size, an integer array a[] and a character array b[], each character is associated with an integer at the same index.

• Sort the character array b[] according to the ascending order of the integer array a[].
• The one-to-one correspondence between integers and characters must be preserved after sorting.

Example:

Input: a[] = {3, 1, 2}, b[] = {'G', 'E', 'K'}
Output: {'E', 'K', 'G'}
Explanation: After sorting the integer array a[] in ascending order as {1, 2, 3}, the characters in b[] are rearranged to match this order, resulting in {'E', 'K', 'G'}.

Approach

Follow these steps to sort the character array according to the integer array:

• Define a Pair class containing an integer and its corresponding character.
• Create an array of Pair objects for all elements in the arrays.
• Sort the Pair array using the integer value as the key.
• Extract the characters from the sorted Pair array and update the character array.

Sorted character array: [E, K, G]

• Time Complexity: O(n log n)
• Space Complexity: O(n)

Note: The sorting order can be either ascending or descending based on the problem requirement or user’s choice.