ExcelFunctions

package Exams;

import java.util.*;
import java.util.stream.Collectors;

public class ExcelFunctions {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        int n = Integer.parseInt(sc.nextLine());

        List<String> headers = Arrays.stream(sc.nextLine().split(",\\s+")).collect(Collectors.toList());

        List<List<String>> matrix = new ArrayList<>(n - 1);

        matrix.add(headers);

        for (int r = 1; r < n; r++) {
            matrix.add(new ArrayList<>());
            String[] tokens = sc.nextLine().split(",\\s+");
            for (int c = 0; c < tokens.length; c++) {
                matrix.get(r).add(tokens[c]);
            }
        }

        String[] commands = sc.nextLine().split("\\s+");
        String option = commands[0];

        switch (option) {
            case "hide":
                String headerToHide = commands[1];
                hideHeader(matrix, headerToHide);
                break;
            case "sort":
                String criteria = commands[1];
                sortHeader(matrix, criteria);
                break;
            case "filter":
                String header = commands[1];
                String value = commands[2];
                filterHeader(matrix, header, value);
                break;
        }
    }

    private static void hideHeader(List<List<String>> matrix, String headerToHide) {
        int indexOfHeader = matrix.get(0).indexOf(headerToHide);

        for (int r = 0; r < matrix.size(); r++) {
            matrix.get(r).remove(indexOfHeader);
        }

        for (int r = 0; r < matrix.size(); r++) {
            System.out.println(String.join(" | ", matrix.get(r)));
        }
    }

    public static void sortHeader(List<List<String>> matrix, String criteria) {
        int headerToSort = matrix.get(0).indexOf(criteria);
        List<String> sortCriteria = new ArrayList<>();

        for (int r = 1; r < matrix.size(); r++) {
            sortCriteria.add(matrix.get(r).get(headerToSort));
        }

        Collections.sort(sortCriteria);

        System.out.println(String.join(" | ", matrix.get(0)));
        for (int i = 0; i < sortCriteria.size(); i++) {
            String element = sortCriteria.get(i);

            for (int r = 1; r < matrix.size(); r++) {
                if (matrix.get(r).get(headerToSort).equals(element)){
                    System.out.println(String.join(" | ", matrix.get(r)));
                }
            }
        }
    }

    private static void filterHeader(List<List<String>> matrix, String header, String value) {
        int headerToFilter = matrix.get(0).indexOf(header);

        System.out.println(String.join(" | ", matrix.get(0)));
        for (int r = 1; r < matrix.size(); r++) {
            if (matrix.get(r).get(headerToFilter).equals(value)){
                System.out.println(String.join(" | ", matrix.get(r)));
            }
        }
    }
}