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1. How many nodes does the suffix trie for aaaa have, counting the root?

45610

2. A trie that stores only the whole text banana, not its suffixes, is asked whether nan is in the text. What does it return?

True, because nan is inside bananaAn exception, because nan is shorter than the stored textFalse, because no stored path spells nan2, because nan occurs twice

3. What does this program print? ``

python
class Node:
    def __init__(self):
        self.next = {}
        self.pass_count = 0


root = Node()
nodes = 1
text = "abab"
for start in range(len(text)):
    node = root
    for i in range(start, len(text)):
        ch = text[i]
        if ch not in node.next:
            node.next[ch] = Node()
            nodes += 1
        node = node.next[ch]
        node.pass_count += 1
print(nodes, root.next["a"].pass_count)

``

7 28 28 15 2

4. What does this program print? ``

python
alphabet = "abcdefghijklmnopqrstuvwxyz"
print(alphabet.find("A"), alphabet.find("z"))

``

-1 250 2525 -1-1 0

5. Which statements about the suffix trie in this lesson are true? Pick all that apply.

Pick every answer that is true.

An uppercase pattern such as A makes count_occurrences raise an exception on a lowercase trieInserting only the whole text answers substring queries as well as inserting every suffixThe pass_count on a node is the number of times the string spelled by that node occurs in the text, overlaps includedWhen the text length doubles, the node count for random DNA letters grows by about four timesAn empty pattern makes count_occurrences raise a ValueError

Suffix tries