Task3

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/**
 *
 * @author 18201147
 */
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.LinkedList;
import java.util.Iterator;

public class Task3 {
    public static int[][] undirectedMatrix(String filename) {
        File file;
        Scanner sc;

        try {
            file = new File(filename);
            sc = new Scanner(file);
        } catch(FileNotFoundException fnfe) {
            System.out.println(filename + " doesn't exist!");
            return null;
        }

        if(!(sc.hasNext() && sc.hasNextInt())) {
            System.out.println("Invalid input format");
            return null;
        }
        int size = sc.nextInt();
        int[][] matrix = new int[size][size];

        while(sc.hasNextInt()) {
            int start = sc.nextInt();
            int end = sc.nextInt();
            matrix[start][end] = 1;
            matrix[end][start] = 1;
        }
        sc.close();
        return matrix;
    }
    public static int[][] directedMatrix(String filename) {
        File file;
        Scanner sc;

        try {
            file = new File(filename);
            sc = new Scanner(file);
        } catch(FileNotFoundException fnfe) {
            System.out.println(filename + " doesn't exist!");
            return null;
        }

        if(!(sc.hasNext() && sc.hasNextInt())) {
            System.out.println("Invalid input format");
            return null;
        }
        int size = sc.nextInt();
        int[][] matrix = new int[size][size];

        while(sc.hasNextInt()) {
            int start = sc.nextInt();
            int end = sc.nextInt();
            matrix[start][end] = 1;
        }
        sc.close();
        return matrix;
    }

    public static LinkedList<Integer>[] undirectedList(String filename) {
        File file;
        Scanner sc;

        try {
            file = new File(filename);
            sc = new Scanner(file);
        } catch(FileNotFoundException fnfe) {
            System.out.println(filename + " doesn't exist!");
            return null;
        }

        if(!(sc.hasNext() && sc.hasNextInt())) {
            System.out.println("Invalid input format");
            return null;
        }
        int size = sc.nextInt();
        LinkedList<Integer>[] collection = new LinkedList[size];
        for(int i = 0; i < size; i++) collection[i] = new LinkedList<>();

        while(sc.hasNextInt()) {
            int start = sc.nextInt();
            int end = sc.nextInt();
            collection[start].add(end);
            collection[end].add(start);
        }
        sc.close();
        return collection;
    }
    public static LinkedList<Integer>[] directedList(String filename){
        File file;
        Scanner sc;

        try {
            file = new File(filename);
            sc = new Scanner(file);
        } catch(FileNotFoundException fnfe) {
            System.out.println(filename + " doesn't exist!");
            return null;
        }

        if(!(sc.hasNext() && sc.hasNextInt())) {
            System.out.println("Invalid input format");
            return null;
        }
        int size = sc.nextInt();
        LinkedList<Integer>[] collection = new LinkedList[size];
        for(int i = 0; i < size; i++) collection[i] = new LinkedList<>();

        while(sc.hasNextInt()) {
            int start = sc.nextInt();
            int end = sc.nextInt();
            collection[start].add(end);
        }
        sc.close();
        return collection;
    }

    public static void printMatrix(int[][] matrix) {
        if(matrix == null) return;
        System.out.print("  ");
        for(int i = 0; i < matrix.length; i++)
            System.out.print(i + " ");
        System.out.println();

        for(int i = 0; i < matrix.length; i++) {
            System.out.print(i + " ");
            for(int j = 0; j < matrix[i].length; j++) {
                System.out.print(matrix[i][j] + " ");
            }
            System.out.println();
        }
    }
    public static void printAdjList(LinkedList<Integer>[] collection) {
        if(collection == null) return;
        for(int i = 0; i < collection.length; i++) {
            System.out.print(i + " -> ");
            Iterator<Integer> itr = collection[i].iterator();
            while(itr.hasNext()) {
                System.out.print(itr.next());
                if(itr.hasNext()) System.out.print(" --> ");
            }
            System.out.println();
        }
    }

    public static void printOutDegOnly(String filename) {
        File file;
        Scanner sc;

        try {
            file = new File(filename);
            sc = new Scanner(file);
        } catch(FileNotFoundException fnfe) {
            System.out.println(filename + " doesn't exist!");
            return;
        }

        if(!(sc.hasNext() && sc.hasNextInt())) {
            System.out.println("Invalid input format");
            return;
        }
        int size = sc.nextInt();
        int[] outdegs = new int[size];

        while(sc.hasNextInt()) {
            int start = sc.nextInt();
            int end = sc.nextInt();
            outdegs[start]++;
            outdegs[end]++;
        }
        sc.close();

        for(int i = 0; i < size; i++) {
            System.out.println(i + " --> " + outdegs[i]);
        }
    }
    public static void printOutInDeg(String filename) {
        File file;
        Scanner sc;

        try {
            file = new File(filename);
            sc = new Scanner(file);
        } catch(FileNotFoundException fnfe) {
            System.out.println(filename + " doesn't exist!");
            return;
        }

        if(!(sc.hasNext() && sc.hasNextInt())) {
            System.out.println("Invalid input format");
            return;
        }
        int size = sc.nextInt();
        int[] outdegs = new int[size];
        int[] indegs = new int[size];

        while(sc.hasNextInt()) {
            int start = sc.nextInt();
            int end = sc.nextInt();
            outdegs[start]++;
            indegs[end]++;
        }
        sc.close();

        for(int i = 0; i < size; i++) {
            System.out.printf("%d --> %d/%d\n", i, outdegs[i], indegs[i]);
        }
    }

    public static void main(String[] args) {
        final String path = System.getProperty("user.dir") + "\\src\\input.txt";

        System.out.println("Undirected Matrix");
        int[][] mat1 = undirectedMatrix(path);
        printMatrix(mat1);

        System.out.println("\nUndirected List");
        LinkedList<Integer>[] adjlist1 = undirectedList(path);
        printAdjList(adjlist1);

        System.out.println("\nUndirected Out degrees only");
        printOutDegOnly(path);

        System.out.println("\nDirected Matrix");
        int[][] mat2 = directedMatrix(path);
        printMatrix(mat2);

        System.out.println("\nDirected List");
        LinkedList<Integer>[] adjlist2 = directedList(path);
        printAdjList(adjlist2);

        System.out.println("\nDirected Out In degrees");
        printOutInDeg(path);
    }
}