DFS

var stack []Node
    stack = append(stack, Node{"", 0})
    seen := make(map[Node]bool)

    for len(stack) > 0 {
        size := len(stack)
        top := stack[len(stack)-1]
        stack = stack[:len(stack)-1]

        if seen[top] {
            continue
        }

        seen[top] = true

        Printer(top) //do stuff

        for i := 0; i < size; i++ {

            for _, val := range graph[top] {
                if !seen[val] {
                    stack = append(stack, val)
                }
            }
        }

    }