MatrixList.java

/*
    Solved By: Sandeep Ranjan (1641012352)
    
    Solution for Programming Project
    5.6
*/
class Node {
	int data;
	Node fLink; //forward
	Node dLink; //down

	Node(int data) {
		this.data = data;
		this.fLink =  this.dLink = null;
	}
}

class Row {
	private int col;
	private Node start;

	public Row(int col) {
		this.col = col;

		generateRow();
	}

	private void generateRow() {

		Node newNode = new Node(-1);
		start = newNode;
		Node p = start;
		
		while(col > 1) {
			Node newN = new Node(-1); 
			p.fLink = newN;
			p = newN;
			col--;
		}
	}

	public Node getStart() {
		return start;
	}
}


class Matrix {
	private int n; //row
	private int m; //col
	private Row[] r;
	private Node start;

	public Matrix(int n, int m) {
		this.n = n;
		this.m = m;
		start = null;
		r = new Row[n];

		check();
		generateMatix();
	}

	private void check() {
		if(n <= 0 || m <= 0) {
			System.out.println("Value of 'n' & 'm' must be greater than 0");
			System.exit(0);
		}
	}

	private void generateMatix() {

		for(int i=0; i<n; i++) {
			r[i] = new Row(m);
		}

		start = r[0].getStart();

		for(int i=0; i<n-1; i++) {
			Node p1 = r[i].getStart();
			Node p2 = r[i+1].getStart();

			for(int j=0; j<m; j++) {
				p1.dLink = p2;
				p1 = p1.fLink;
				p2 = p2.fLink;
			}
		}
	}

	public void insert (int x, int y, int data) {
		Node cell = start;
		int col = y;

		if(x > n || y > m || x <= 0 || y <= 0) {
			System.out.println("(x,y) such that 0 < x < "+ n + " and 0 < y < " + m + ".");
			return;
		}

		for(int row=1; row<x; row++) {
			cell = cell.dLink;
		}

		while(col>1) {
			cell = cell.fLink;
			col--;
		}

		cell.data = data;
	}

	public void display() {
		Node row = start;

		while(row != null) {
			Node cell = row;
			while(cell != null) {
				System.out.print(cell.data + " ");
				cell = cell.fLink;
			}
			System.out.println();
			row = row.dLink;
		}

		System.out.println();
	}
}

class MatrixList {
	public static void main(String[] args) {
		Matrix m = new Matrix(2,2);
		m.display(); //Empty 

		//Value filling
		m.insert(1,0,23);
		m.insert(1,2,13);
		m.insert(2,1,43);
		m.insert(2,2,41);
		m.display(); //After filling
	}
}