Alien Dictionary - Failing Few Test Cases

Questions: Specific question not provided.

Example test case that fails (the order is reported as "", but the correct one is "acbz"):

vector<string> words2 = {"ac","ab","zc","zb"};
string res2 = alienOrder(words2);
cout << "Alien Order: " << res2 << endl;

Candidate's Approach

The candidate implemented a BFS solution for the Alien Dictionary problem. The approach involves:

Building a graph from the given words, where each character is a node and directed edges represent the order of characters.
Using an indegree array to track the number of incoming edges for each character.
Performing a BFS to determine the order of characters, starting from nodes with zero indegree.
The candidate noted that the solution fails for certain test cases, specifically returning an empty string instead of the expected order.

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