import java.util.Scanner;

public class Graph {
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.print("Please insert a odd number: ");
        int n = in.nextInt();
        //validation n is odd.
        while (n % 2 == 0) {
            System.out.print("u have insert an even number, let's try again: ");
            n = in.nextInt();
        }
        System.out.println("That's correct -> n= " + n + ';');
        //create a NxN matrix;
        int[][] adjancecyM = new int[n][n];
        int i, j, cnt, random, sum = 0,degreeVertex=0,degreeMax=0,degreeMin=1000000,degreeTotal=0;
        System.out.println("Which matrix would like to see ?");
        System.out.println("--------------------------------");
        System.out.print("1.G complete\n2.G cycle\n3.G random\nPlease enter a number: ");
        cnt = in.nextInt();
        switch (cnt) {
            //G is the complete graph
            case 1:
                for (i = 0; i < adjancecyM.length; ++i)
                    for (j = 0; j < adjancecyM.length; ++j)
                        if (i != j) adjancecyM[i][j] = adjancecyM[j][i] = 1;
                System.out.println("Edges: " + (n * (n - 1) / 2));
                break;
            //G cycle
            case 2:
                for (i = 0; i < adjancecyM.length - 1; ++i) {
                    adjancecyM[i][i + 1] = 1;
                }
                adjancecyM[adjancecyM.length - 1][0] = 1;

                System.out.println("Edges: " + n);
                break;
            //G random
            case 3:
                for (i = 0; i < adjancecyM.length; ++i)
                    for (j = 0; j < adjancecyM.length; ++j) {
                        if (((int) (Math.random() * 2) == 1) && i != j) {
                            adjancecyM[i][j] = 1;
                            sum++;
                        } else
                            adjancecyM[i][j] = 0;
                    }
                System.out.println();
                if (sum > 1 && sum % 2 == 1) System.out.println("Edges: " + ((sum + 1) / 2));
                else if (sum > 1 && sum % 2 == 0) System.out.println("Edges: " + sum);
                else
                    System.out.println("Graf doesn't create");
                break;

            default:
                System.out.println("Pick another number!");
        }
        //Afisare
        System.out.println("Adjancecy Matrix");
        System.out.println("----------------");
        for (i = 0; i < adjancecyM.length; ++i) {
            for (j = 0; j < adjancecyM.length; ++j)
                System.out.print(adjancecyM[i][j] + " ");
            System.out.println();
        }
        //minimum and max degrees of a vertex
        for (i = 0; i < adjancecyM.length; i++)
        {
            degreeVertex=0;
            for(j=0 ; j < adjancecyM.length ; j++)
                if(adjancecyM[i][j] == 1){
                    degreeVertex++;
                    degreeTotal++;
                }

                if(degreeVertex > degreeMax) degreeMax=i;
                if(degreeVertex < degreeMin) degreeMin=i;
                System.out.println("For vertex: " + i + " degree is " + degreeVertex);
        }
        System.out.println("Max vertex: " + degreeMax + " and Min vertex: " +degreeMin);
        if(degreeTotal == 2*sum) System.out.println("Equal!");
            else
            System.out.println("Degrees != 2*Edges");

    }
}