this is a clever way to check if a node is a neighbor of another, but it would be better to combine your if and else if into one check. only return false if first is a neighbor of second and second is a neighbor of first. if someone were to hardcode one as a neighbor but not vice versa, this could cause an issue

for this random graph, you don't add n random nodes to the graph, you always add specific nodes 0 through n-1

this code could potentially generate the same 2 random numbers, so you would add an edge from a node to itself

you are covering the case of not returning the path if the destination node is not in the path, but the problem said to return null and not an empty array

for this if statement the and symbol should be &&, doing one & will throw an error

your BFT looks good, but your code won't cover the case of if the graph contains any disconnected nodes

for your random DAG, when you generate 2 random nodes to add an edge to you don't check to make sure the edge is not going backwards. this would create a cycle in the graph and a DAG is acyclic

for this random DAG, you don't add n random nodes to the graph, you always add specific nodes 0 through n-1

this could potentially generate the same random number, and so you would add an edge from a node to itself

you could save memory space by just using one stack and making your helper method a void method

Yo. Here's a code review.

No roasting needed, even though this is java.

You're probably running into situations where the same node is being randomly generated for graphs that only have a few nodes. You could increase the bound.