数据结构实现代码理解

Question

Im taking a course in algorithms and data structers, and my instructor wants me to implement several data structers (such as BST, stack etc.), and algorithms (such as quick search, DFS, etc.). I want to belive that I understand the basics, but everytime Im starting to plan the code I have the same difficulty:

here's my current assigment: my instructor wants me to implement a DFS (depth first search) for a directed graph (using c++).

my question is- how do I suppose to implement the graph? should I use adjacency matrix? or should I use adjacency list? neither this nor that?? so I asked my instructor, and his answare was this: "think of the graph as a black box "... more confused than before, I rashed to stackoverflow , and here i am posting this question... I dont look for someone to tell me how to implement DFS (or any other algorithm- I can google too!)- I just need someone to explain what should I get as input, and what should I provide as output?

I'll appreciate any comment! thanks!

Answer 1

What he means by a black box is just that you cannot see the nodes and how they connect before you do your DFS. You will probably just get the root node and your algorithm with have to explore from there. As for what you should output- that depends on the assignment. Are you looking for specific data? if not, perhaps a detail of which nodes were visited in which order.