Challenge 3: Detect Cycle in Graph

Problem statement

The concept of loops or cycles is very common in graph theory. A cycle exists when you traverse the graph and come upon a vertex that has already been visited.

Note: Your solution should work for both connected and unconnected graphs.

You have to implement the detectCycle function, which tells you whether or not a graph contains a cycle.

Input

The input is a graph in the form of an adjacency list.

Note: You can start the traversal from any vertex.

Output

true if a cycle exists but it is false if it doesn’t.

Sample input

graph = {
    0 -> 1 
    1 -> 2
    2 -> 0
}

Sample output

true