LESSON 625 OF 677 · PROJECTS: COMMAND-LINE TOOLS

CLI Tool: sort v1 — Ascending Alphabetical Sort

Practice

Build a tiny version of the Unix sort command. Given a list of lines, return them sorted in ascending order by character code (like LC_ALL=C sort: uppercase letters come before lowercase ones, "Zebra" before "apple", and an empty line comes first), joined by newline characters (\n). Duplicates are all kept. If the list is empty, return the empty string.

Function signature:

fun sortLines(lines: Array<String>): String

Example:

Input: lines = ["banana", "apple", "cherry"]

Output: "apple\nbanana\ncherry"

When printed:
apple
banana
cherry

Convert the array into a mutable list, sort it in place with sort(), then combine it with joinToString("\n").

The full solution:

class Solution {
    fun sortLines(lines: Array<String>): String {
        val sortedLines = lines.toMutableList()
        sortedLines.sort()
        return sortedLines.joinToString("\n")
    }
}

STEP 1 OF 3

Guided

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