How to add elements to a vector and traverse it simultaneously? - c++

Question

I want to perform BFS on a tree, to find out a certain leaf, but the graph is dynamic in nature, when I land on a leaf and that leaf isn't the one I am looking for, then its children are computed from the leaf (The leaf is no longer a leaf it is a node).
I tried two implementations , and both produced erronous results. I think the pointers are getting invalidated or this is an incorrect implementation. My code is as follows
int y=0;
while(graph.end() - graph.begin() < 262145 and graph.end() - graph.begin() < y){
if(found(graph[y])){
clock2 = graph[y];
break;
}
else{
if(graph[y].b[0] < 4) graph.push_back(move1(graph[y]));
if(graph[y].b[1] < 4) graph.push_back(move2(graph[y]));
}
y++;
}
and the next implementation was something like this
for(vector<foo> :: iterator i = graph.begin();i!=graph.end();i++){
if(found(*i)){
clock2 = *i;
break;
}
else{
if(i->b[0] < 4) graph.push_back(move1(*i));//move1 and move2 are
if(i->b[1] < 4) graph.push_back(move2(*i));//functions of return type foo
}
}
Both of these are causing the programme to crash. What is wrong with them, how to implement these? Please comment with additional queries.

Answer 1

I am a little confused as too what exactly is going on and what exactly you are asking. But if you are asking how to preform a simple BFS on a graph here is some sample code that I find pretty easy to read.
Comment further and I will change it to try and match the exact criteria of the question (once I have some more clarity that is)
struct node{
std::vector children<node*>;
int data;
}
void bfs(node* root, int value){ // THIS IS CHECK FOR INTS so change for whatever value
if(!root) return;
std::queue myq;
myq.push(root);
node* toCheck;
while(!myq.Empty()){
toCheck = myq.top();
myq.pop();
if(toCheck->data == value){
//do whatever you want with that information
}else{
/*
//forloop/whileloop as many times as necessary to set all the new children
//Example:
node* newNode = new node();
newNode->data = someValue; // just some information that you want to add
toCheck->children.push_back(newNode);
*/
}
for(int i = 0; i < toCheck->children.size(); i++){
myq.push(toCheck->children[i]);
}
}
}