java - breadth first search error -

public int bfs(int maxdepth){ //maxdepth = 3 works.. maxdepth = 4 gives me error         int src = 0;         int dest = 2;         int nodes = arr[src].length - 1;         boolean[] visited = new boolean[nodes + 1];         int i;         int countdepth = 0;         int countpaths = 0;         int element;           queue.add(src);          while(!queue.isempty() || countdepth != maxdepth)         {             element = queue.remove();             = element;              while(i <= nodes)             {                 if(arr[element][i] > 0 && visited[i] == false)                 {                     queue.add(i);                     visited[i] = true;                      if(arr[i][element] > 0) //if has 2 directions                         visited[i] = false;                      if(element ==  dest || == dest)                         countpaths++;                 }                  i++;             }              countdepth++;         }          return countpaths;     } 

i'm trying go 'x' amount of levels deep while counting # of paths destination.

for reason keep getting error:

 exception in thread "main" java.util.nosuchelementexception @ java.util.linkedlist.removefirst(unknown source) @ java.util.linkedlist.remove(unknown source) @ graph.bfs(graph.java:48) 

i don't understand what's going on. seems work when go 3 levels deep when change 4, doesn't work.

change

while(!queue.isempty() || countdepth != maxdepth)

to

while(!queue.isempty() && countdepth != maxdepth)

each graph has maximal depth. seems, set maxdepth larger it's possible given graph , loop tries continue bfsing after handling possible nodes (i.e when queue empty)

update try provide answer second question posted in comments if given information not enough, so, try extrasens=) guess, going calculate paths of length=1, of length=2.. length=givenmaxdepth|maxpossibledepth. saw queue data structure didn't see declaration - are using same queue function calls? if yes, should clear queue after each call (best place call queue.clear() before return statement).

also, see using new visited array in each call , it's correct if using global visited should "clear" visited after each call - in other words fill false.