What exactly does {-1} mean!

  • 3

    I got Runtime error for this test case even with the below code:

    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
    return NULL;

    Can someone tell me what does {-1} mean here and why I got Runtime error? It has been so frustrating.

  • 0

    It means the label of the input node is -1 and has no neighbor, while your return value is NULL, so you get a Runtime error, you should return a deep copy.

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