Question

I am trying to explore a graph here but I am not sure what is wrong with the explore function. The recursion doesn’t seem to be working correctly; while exploring the neighbours of the node 0 it explored 0, 1, 2 and then never returns back to explore 3, 4, 5; why is that so?

explored=[]
//class definition 
function graph(){
    this.graph=new Array();
    this .graph[0] = [1,0,1,1,0,1]
    this .graph[1] = [0,1,1,1,0,0]
    this .graph[2] = [1,1,1,1,0,0]
    this .graph[3] = [1,1,1,1,1,0]
    this .graph[4] = [0,0,0,1,1,0]
    this .graph[5] = [1,0,0,0,0,0]

    this.explore    = explore

}

function explore(node,depth){

    explored[node]=1
    document.write('<br>')
    for(x=0;x<depth;x++)
        document.write('-')
    document.write(node+'<br>')
    neighbours=this.graph[node]

    document.write('exploring '+node +' neighbours' + neighbours +'explored = '+explored)

    for ( i=0;i<neighbours.length;i++){
        document.write('checking'+i+' node is ='+node )
        if(neighbours[i] ==1 && explored[i]!=1)
            this.explore(i,++depth)
    }

}

g = new graph()
g.explore(0,0)  

Answer 1

by leaving out var you’re setting global variables in a recursive function and stepping on your toes, here’s the corrected code

function explore(node,depth){

    explored[node]=1
    document.write('<br>')
    for(**var** x=0;x<depth;x++)
        document.write('-')
    document.write(node+'<br>')
    **var** neighbours=this.graph[node]

    document.write('exploring '+node +' neighbours' + neighbours +'explored = '+explored)

    for (**var** i=0;i<neighbours.length;i++){
        document.write('checking'+i+' node is ='+node )
        if(neighbours[i] ==1 && explored[i]!=1)
            this.explore(i,++depth)
    }

}