thecoded.prof
CMU Coding Bootcamp
feat: oct 10 level 0
+175
+175
python/oct10/level0/odometer.py
+175
python/oct10/level0/odometer.py
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from typing import List, Optional
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class Odometer:
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"""An odometer where all digits must be in ascending order"""
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miles: int
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@staticmethod
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def _is_error(miles: int) -> bool:
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"""Return True if the given miles are not in ascending order or contain a zero."""
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try:
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Odometer(miles)
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except ValueError:
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return True
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return False
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@staticmethod
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def possible_values(odo_len: int) -> List[int]:
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"""Return a list of possible values for the given miles."""
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min = Odometer._get_minimum(odo_len)
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max = Odometer._get_maximum(odo_len)
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return [i for i in range(min, max + 1) if not Odometer._is_error(i)]
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@staticmethod
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def _ascending(digits: List[int]) -> bool:
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return all(digits[i] < digits[i + 1] for i in range(len(digits) - 1))
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@staticmethod
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def _get_digits(miles: int) -> List[int]:
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"""Return a list of digits from the given miles."""
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return list(map(int, str(miles)))
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@staticmethod
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def _verify_miles(miles: int) -> None:
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"""Verify that the given miles are in ascending order and do not contain a zero. Throws ValueError if not."""
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digits = Odometer._get_digits(miles)
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if len(digits) > 9:
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raise ValueError("Miles cannot be greater than 9 digits")
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if not Odometer._ascending(digits):
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raise ValueError("Miles must be in ascending order")
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if any(d == 0 for d in digits):
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raise ValueError("Miles cannot contain a zero")
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@staticmethod
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def _get_maximum(odo_len: int) -> int:
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"""Return the maximum possible miles given the current odometer length."""
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return int("".join([str(i) for i in range(10 - odo_len, 10)]))
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@staticmethod
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def _get_minimum(odo_len: int) -> int:
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"""Return the minimum possible miles given the current odometer length."""
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return int("".join([str(i) for i in range(1, odo_len + 1)]))
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def __init__(self, starting_miles: int = 1) -> None:
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"""Initialize an odometer with the given starting miles."""
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if starting_miles < 0:
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raise ValueError("Starting miles cannot be negative")
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Odometer._verify_miles(starting_miles)
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self.miles = starting_miles
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def verify_miles(self) -> bool:
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"""Verify that the odometer's miles are in ascending order and do not contain a zero."""
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try:
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Odometer._verify_miles(self.miles)
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except ValueError:
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return False
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return True
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def get_digits(self) -> List[int]:
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"""Return the odometer's miles as a list of digits."""
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return list(map(int, str(self.miles)))
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def get_minimum(self) -> int:
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"""Return the minimum valid odometer reading."""
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return Odometer._get_minimum(len(self.get_digits()))
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def get_maximum(self) -> int:
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"""Return the maximum valid odometer reading."""
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return Odometer._get_maximum(len(self.get_digits()))
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def next_reading(self) -> Optional[int]:
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"""Return the next valid odometer reading."""
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first_run = True
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if self.miles == self.get_maximum():
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return None
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while not self.verify_miles() or first_run:
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first_run = False
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self.miles += 1
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return self.miles
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def previous_reading(self) -> Optional[int]:
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"""Return the previous valid odometer reading."""
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first_run = True
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if self.miles == self.get_minimum():
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return None
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while not self.verify_miles() or first_run:
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first_run = False
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self.miles -= 1
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return self.miles
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def nth_reading_after(self, n: int) -> Optional[int]:
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"""Return the nth valid odometer reading."""
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first_run = True
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i = 0
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while not self.verify_miles() or first_run or i < n:
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if self.miles == self.get_maximum():
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return None
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first_run = False
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self.miles += 1
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if self.verify_miles():
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i += 1
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return self.miles
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def nth_reading_before(self, n: int) -> Optional[int]:
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"""Return the nth valid odometer reading before the current one."""
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first_run = True
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i = 0
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while not self.verify_miles() or first_run or i < n:
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if self.miles == self.get_minimum():
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return None
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first_run = False
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self.miles -= 1
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if self.verify_miles():
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i += 1
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return self.miles
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@staticmethod
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def print(start: Optional[int], end) -> None:
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"""Print the start of the odometer with some other value."""
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print(f"{start} -> {end}")
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@staticmethod
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def _distance(start: int, end: int) -> int:
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"""Calculate the distance between two odometer readings."""
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odo_len = len(Odometer._get_digits(start))
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if odo_len != len(Odometer._get_digits(end)):
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raise ValueError("Odometer readings must have the same number of digits")
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n = 0
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while start != end:
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try:
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Odometer._verify_miles(start)
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n += 1
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if start == Odometer._get_maximum(odo_len):
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start = Odometer._get_minimum(odo_len)
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else:
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start += 1
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except:
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start += 1
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return n
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def distance(self, end: int) -> Optional[int]:
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"""Calculate the distance between the current odometer reading and another."""
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try:
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return Odometer._distance(self.miles, end)
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except:
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return None
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odometer = Odometer(2467)
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Odometer.print(odometer.miles, odometer.get_minimum())
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Odometer.print(odometer.miles, odometer.get_maximum())
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Odometer.print(odometer.miles, odometer.nth_reading_after(6))
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Odometer.print(odometer.miles, odometer.nth_reading_before(6))
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Odometer.print(odometer.miles, odometer.next_reading())
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Odometer.print(odometer.miles, odometer.previous_reading())
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Odometer.print(odometer.miles, f"1234: {odometer.distance(1234)}")
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odo2 = Odometer(123)
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Odometer.print(odo2.miles, odo2.get_minimum())
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Odometer.print(odo2.miles, odo2.get_maximum())
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Odometer.print(odo2.miles, odo2.nth_reading_after(83))
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Odometer.print(odo2.miles, f"123: {odo2.distance(123)}")
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print(Odometer.possible_values(8))