math - Are these test cases correct? -
while working on google foobar problems, ran 1 following prompt:
professor boolean, notorious mad scientist, found out precious rabbit specimen has escaped! rushes call security minions on lab phone. however, rabbit escapee hacked phone speed escape! left sign following clues: each digit dialed has number can reached knight chess piece last digit dialed - is, must move precisely 2 spaces in 1 direction, , 1 space in perpendicular direction dial next correct number. can dial number want start with, subsequent numbers must obey knight's move rule.
the lab phone has numbers arranged in following way: 1, 2, 3 in first row; 4, 5, 6 in second row; 7, 8, 9 in third row; , blank, 0, blank in fourth row.
1 2 3 4 5 6 7 8 9 0
for example, if dialed 1, next number dial has either 6 or 8. if dialed 6, next number must 1 or 7.
professor boolean wants find out how many different phone numbers can dial under these conditions. write function called answer(x, y, z) computes number of phone numbers 1 can dial start digit x, end in digit y, , consist of z digits in total. output number string representing number in base-10.
x , y digits 0 9. z between 1 , 100, inclusive.
test cases
inputs: (int) x = 6 (int) y = 2 (int) z = 5 output: (string) "6"
inputs: (int) x = 1 (int) y = 5 (int) z = 100 output: (string) "0"
inputs: (int) x = 3 (int) y = 7 (int) z = 1 output: (string) "0"
i feel first test case wrong because after drawing out decision tree numbers find possible 61672, 67272, 67292, 67672, four. there i'm misinterpreting or missing problem?
i don't think test case wrong, statement
if dialed 6, next number must 1 or 7.
is wrong. not being able 6 0 makes problem not make sense. comment, blanks aren't valid moves, have 6 -> 0 being valid?
1 2 3 4 5 6 7 8 9 0
obviously 6 -> 0 valid move, no blanks involved.
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