Answer:
Step-by-step explanation:
Convert the regular expression r into an equivalent finite automaton (NFA or DFA) using standard algorithms like Thompson's construction or subset construction.
Initialize an empty set to store the shortest words found.
Initialize a queue data structure and enqueue the initial state of the automaton.
While the queue is not empty, do the following steps:
a. Dequeue a state from the queue.
b. If the state is a final state and its word length is greater than 0, add the word associated with that state to the set of shortest words.
c. For each outgoing transition from the current state, do the following:
Enqueue the next state.
Append the symbol of the transition to the current word.
If the length of the current word is less than or equal to the length of the previously found shortest words, enqueue the next state.
Once the queue is empty, the set of shortest words will contain all the shortest words in the regular language defined by the regular expression r.
Return the set of shortest words as the result.