MasterFile.java

import java.io.*;
import java.util.*;

public class SafeOrbits {
    public static void main(String[] args) throws Exception {
        Scanner fileName = new Scanner(System.in);
        System.out.println("Please enter filename: ");
        Scanner inputFile = new Scanner(new File(fileName.nextLine()));
        fileName.close();
        
        List<Double> list = new ArrayList<>();
        
        while (inputFile.hasNextLine()) {
            String[] line = inputFile.nextLine.split(",");
            list.add(Double.parseDouble(line[1]))
        }
        inputFile.close();
        
        Collections.sort(list);
        Double minDiff = Double.MAX_VALUE;
        Double SAFE_DIST = 5;
        
        for (int i = 1; i < list.size(); i++) {
            minDiff = Math.min(list.get(i) - list.get(i-1), minDiff);
        }
            
        System.out.println("They are " + (minDiff < SAFE_DIST ? "not " : "") + "in safe orbits");
        System.out.println("The minimum distance between orbits (km): " + minDiff);
    }
}

public class MaxFrequency {
    public static void main(String[] args) throws Exception {
        Scanner fileName = new Scanner(System.in);
        System.out.println("Please enter filename: ");
        Scanner inputFile = new Scanner(new File(fileName.nextLine()));
        fileName.close();
        
        String maxKey = null;
        int maxFreq = 0;
        Map<String, Integer> map = new TreeMap<>();
        
        while (inputFile.hasNextLine()) {
            String word = inputFile.nextLine();
            Integer freq = map.get(word);
            map.put(word, (freq == null) ? 1 : freq + 1);
        }
        inputFile.close()
        
        for (String key : map.keySet()) {
            int freq = map.get(key);
            System.out.println("Word: " + key + ", Frequency: " + freq);
            if (freq > maxFreq) {
                maxFreq = freq;
                maxKey = key;
            }
        }
        
        System.out.println("\nMaximum: " + maxKey + ", " + maxFreq);
    }
}

public class DuplicateCheck {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int num;
        System.out.println("Enter sequence of numbers: ");
        
        List<Integer> list = new ArrayList<>();
        
        do {
            num = input.nextInt();
            list.add(num);
        } while (num >= 0);
        input.close();
        
        Set<Integer> set = new TreeSet<>(list);
        
        System.out.println("They are " + ((set.size() < list.size()) ? "not " : "") + "distinct" );
        System.out.println("Sorted elements: " + set);
    }
}