# Find indegree and outdegree of a directed graph in scala

Scala program for Find indegree and outdegree of a directed graph. Here problem description and other solutions.

``````/*
Scala Program for
Show degree of vertex in directed graph
*/
class AjlistNode(
// Vertices node key
var id: Int,
var next: AjlistNode)
{
def this(id: Int)
{
// Set value of node key
this(id, null);
}
}
class Vertices(var data: Int,
var next: AjlistNode,
var last: AjlistNode)
{
def this(data: Int)
{
this(data, null, null);
}
}
class Graph(
// Number of Vertices
var size: Int,
var node: Array[Vertices])
{
def this(size: Int)
{
this(size, Array.fill[Vertices](size)(null));
// Set value
this.setData();
}
// Set initial node value
def setData(): Unit = {
if (size <= 0)
{
println("\nEmpty Graph");
}
else
{
var index: Int = 0;
while (index < size)
{
// Set initial node value
node(index) = new Vertices(index);
index += 1;
}
}
}
//  Handling the request of adding new edge
def addEdge(start: Int, last: Int): Unit = {
if (start >= 0 && start < size &&
last >= 0 && last < size)
{
// Safe connection
var edge: AjlistNode = new AjlistNode(last);
if (node(start).next == null)
{
node(start).next = edge;
}
else
{
// Add edge at the end
node(start).last.next = edge;
}
// Get last edge
node(start).last = edge;
}
else
{
// When invalid nodes
println("\nHere Something Wrong");
}
}
def printGraph(): Unit = {
if (size > 0)
{
var index: Int = 0;
// Print graph ajlist Node value
while (index < size)
{
print("\nAdjacency list of vertex " + index + " : ");
var temp: AjlistNode = node(index).next;
while (temp != null)
{
// Display graph node
print(" " + node(temp.id).data);
// Visit to next edge
temp = temp.next;
}
index += 1;
}
}
}
// Find indegree and outdegree of
// each nodes of a given graph
def findDegree(indegree: Array[Int],
outdegree: Array[Int]): Unit = {
var temp: AjlistNode = null;
var length: Int = 0;
var i: Int = 0;
while (i < this.size)
{
temp = this.node(i).next;
length = 0;
while (temp != null)
{
// Update indegree
indegree(temp.id) += 1;
temp = temp.next;
length += 1;
}
// Set outdegree value
outdegree(i) = length;
i += 1;
}
}
def showDegree(): Unit = {
if (this.node != null)
{
var indegree: Array[Int] = Array.fill[Int](this.size)(0);
var outdegree: Array[Int] = Array.fill[Int](this.size)(0);
// Find degree
this.findDegree(indegree, outdegree);
println("\n");
var i: Int = 0;
// Display result
while (i < this.size)
{
println("Node [" + i +
"] indegree [" +
indegree(i) + "] outdegree [" +
outdegree(i) + "]");
i += 1;
}
}
else
{
print("Empty Graph");
}
}
}
object Main
{
def main(args: Array[String]): Unit = {
// 6 implies the number of nodes in graph
var g: Graph = new Graph(6);
// Connected two node with Edges
g.printGraph();
// Test
g.showDegree();
}
}``````

Output

``````Adjacency list of vertex 0 :  1 2 5
Adjacency list of vertex 1 :
Adjacency list of vertex 2 :  3
Adjacency list of vertex 3 :  1
Adjacency list of vertex 4 :  0 1
Adjacency list of vertex 5 :  0 2

Node [0] indegree [2] outdegree [3]
Node [1] indegree [3] outdegree [0]
Node [2] indegree [2] outdegree [1]
Node [3] indegree [1] outdegree [1]
Node [4] indegree [0] outdegree [2]
Node [5] indegree [1] outdegree [2]``````

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