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LESSON 615 OF 667 · 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:

string sortLines(vector<string> lines)

Example:

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

Output: "apple\nbanana\ncherry"

When printed:
apple
banana
cherry

Copy the input vector, call std::sort on it (default ascending, which compares by character code), then concat the results into a single string with "\n" separators.

The full solution: 
class Solution {
public:
    string sortLines(vector<string> lines) {
        vector<string> sortedLines = lines;
        sort(sortedLines.begin(), sortedLines.end());
        string result;
        for (int i = 0; i < sortedLines.size(); i++) {
            if (i > 0) result += "\n";
            result += sortedLines[i];
        }
        return result;
    }
};

STEP 1 OF 7
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