FastPrep
Problem Β· Sorting

Custom Sort String

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Problem statement

AWS provides several utilities for language processing. Develop a helper service to sort a list of strings based on a custom order of characters.

More formally, you are given a custom alphabet system that consists of exactly k characters. Their sorted alphabetical order is given by a string of distinct characters, order. An array arr contains n strings to sort according to the special ordering. Each string in arr contains only characters in order.

Note: A string x = x1x2 ... xn is lexicographically smaller than string y = y1y2 ... ym if either n < m and x1 = y1, x2 = y2, ... xn = ym, or exists some number r (1 ≀ r < n, r < m), such that x1 = y1, x2 = y2, ... xr-1 = yr-1, xr < yr.

Function

customSortString(order: String, arr: String[]) β†’ String[]

Complete the function customSortString in the editor below.

customSortString has the following parameters:

  1. string order: the custom order alphabet of k characters
  2. string arr[n]: the strings to sort

Returns

string(s): the sorted strings

🧑 Endless gratitude to the best 🌷spike🌷! 🧑

Examples

Example 1

order = "9AacB"arr = ["BBBBa", "BBBB9", "B9ca", "Aa999", "B9A", "B", "B9A"]return = ["Aa999", "B", "B9A", "B9A", "B9ca", "BBB89", "BBBBa"]

order = "9AacB" so 'A' comes before 'B', '9' comes before 'B', 'A' comes before 'c', 'c' comes before 'B', '9' comes before 'a'.

The sorted order of strings is ["Aa999", "B", "B9A", "B9A", "B9ca", "BBB89", "BBBBa"].

Example 2

order = "yYaAbBl"arr = ["Yay", "yaY", "lyab", "lyab", "b", "bay"]return = ["yaY", "Yay", "b", "bay", "lyab", "lyaB"]
tomtom highly recommend to go with this highlighted explanation - For example 2, order = "yYaAbB1". The last character might supposed to be letter l, not number one. hard to say. In the explanation they use number one, but it looks like letter l in the example. Regardless, make sure it's both letter l in arr and order or both number one in arr and order. - by spike in Nov 2024 :) ( οΌΎβ—‘οΌΎ)γ£βœ‚πŸ’” -Λ‹Λβœ„β”ˆβ”ˆβ”ˆβ”ˆ-Λ‹Λβœ„β”ˆβ”ˆβ”ˆβ”ˆ-Λ‹Λβœ„β”ˆβ”ˆβ”ˆβ”ˆ-Λ‹Λβœ„β”ˆβ”ˆβ”ˆβ”ˆ-Λ‹Λβœ„β”ˆβ”ˆπŸ§‘ 🐝 Original explanation from the source that is likely to be wrong -

order = "yYaAbB1" so 'y' comes before 'Y', 'Y' is before 'b', 'b' is before '1', 'y' is before 'a' and 'b' is before 'B'.

The sorted order of strings is ["yaY", "Yay", "b", "bay", "lyab", "lyaB"].

Example 3

order = "7BbAz"arr = ["Abb", "A7z", "z7AAAA", "BbbABB"]return = ["BbbABB", "A7z", "Abb", "z7AAAA"]
Example 3 illustration
The sorted srings are ["BbbABB", "A7z", "Abb", "z7AAAA"]

Constraints

  • 1 ≀ k ≀ 62
  • 1 ≀ n ≀ 10^5
  • The sum of lengths of all strings in arr does not exceed 10^6.
  • All characters of arr[] are present in order.
  • All characters of order are distinct and consist of [a-zA-Z0-9] only.

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public String[] customSortString(String order, String[] arr) {
  // write your code here
}
order"9AacB"
arr["BBBBa", "BBBB9", "B9ca", "Aa999", "B9A", "B", "B9A"]
expected["Aa999", "B", "B9A", "B9A", "B9ca", "BBB89", "BBBBa"]
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