Anonymous Threat New Divide

import com.sun.source.tree.IfTree;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class AnonymousThreat {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String lineToMOrD = scanner.nextLine();
        List<String> lineToList = Arrays.stream(lineToMOrD.split("\\s+")).collect(Collectors.toList());
        String command = "";

        while (!"3:1".equals(command = scanner.nextLine())) {
            String[] commArr = command.split("\\s+");
            switch (commArr[0]) {
                case "merge":

                    int startIndex = Integer.parseInt(commArr[1]);
                    int endIndex = Integer.parseInt(commArr[2]);


                    String toMerge = "";


                    if (startIndex < 0) {
                        startIndex = 0;
                    } else if (startIndex > lineToList.size() - 1) {
                        startIndex = lineToList.size() - 1;
                    }

                    if (endIndex > lineToList.size() - 1) {

                        endIndex = lineToList.size() - 1;

                    } else if (endIndex < 0) {
                        endIndex = 0;
                    }

                    for (int i = startIndex; i < endIndex; i++) {

                        toMerge = lineToList.get(i) + lineToList.get(i + 1);

                        lineToList.set(startIndex, toMerge);

                        lineToList.remove(i + 1);

                        endIndex--;
                        i -= 1;
                    }


                    break;
                case "divide":

                    List<String> add = new ArrayList<>();
                    int indexDiv = Integer.parseInt(commArr[1]);
                    int parts = Integer.parseInt(commArr[2]);
                    String checkIfDiv = lineToList.get(indexDiv);
                    int subsLength = checkIfDiv.length() / parts;


                    if (checkIfDiv.length() % parts != 0) {
                        parts--;
                        for (int i = 0; i < parts; i++) {
                            add.add(checkIfDiv.substring(0, subsLength));
                            checkIfDiv = checkIfDiv.replace(checkIfDiv.substring(0, subsLength), "");
                        }

                        add.add(checkIfDiv);
                        lineToList.remove(indexDiv);
                        lineToList.addAll(indexDiv, add);

                    } else {
                        for (int i = 0; i < parts; i++) {
                            add.add(checkIfDiv.substring(0, subsLength));
                            checkIfDiv = checkIfDiv.replace(checkIfDiv.substring(0, subsLength), "");
                        }

                        lineToList.remove(indexDiv);
                        lineToList.addAll(indexDiv, add);
                    }

                    break;
            }

            }
        System.out.println(lineToList.toString().replaceAll("[\\[\\],]",""));
        }



    }