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7271c0d64a
* Update rod_cutting.py A hopefully clearer implementation without dependence on global variables. * Update rod_cutting.py added doctests * Update rod_cutting.py * Update rod_cutting.py
58 lines
1.7 KiB
Python
58 lines
1.7 KiB
Python
from typing import List
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def rod_cutting(prices: List[int],length: int) -> int:
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"""
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Given a rod of length n and array of prices that indicate price at each length.
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Determine the maximum value obtainable by cutting up the rod and selling the pieces
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>>> rod_cutting([1,5,8,9],4)
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10
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>>> rod_cutting([1,1,1],3)
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3
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>>> rod_cutting([1,2,3], -1)
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Traceback (most recent call last):
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ValueError: Given integer must be greater than 1, not -1
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>>> rod_cutting([1,2,3], 3.2)
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Traceback (most recent call last):
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TypeError: Must be int, not float
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>>> rod_cutting([], 3)
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Traceback (most recent call last):
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AssertionError: prices list is shorted than length: 3
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Args:
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prices: list indicating price at each length, where prices[0] = 0 indicating rod of zero length has no value
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length: length of rod
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Returns:
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Maximum revenue attainable by cutting up the rod in any way.
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"""
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prices.insert(0, 0)
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if not isinstance(length, int):
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raise TypeError('Must be int, not {0}'.format(type(length).__name__))
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if length < 0:
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raise ValueError('Given integer must be greater than 1, not {0}'.format(length))
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assert len(prices) - 1 >= length, "prices list is shorted than length: {0}".format(length)
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return rod_cutting_recursive(prices, length)
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def rod_cutting_recursive(prices: List[int],length: int) -> int:
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#base case
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if length == 0:
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return 0
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value = float('-inf')
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for firstCutLocation in range(1,length+1):
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value = max(value, prices[firstCutLocation]+rod_cutting_recursive(prices,length - firstCutLocation))
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return value
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def main():
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assert rod_cutting([1,5,8,9,10,17,17,20,24,30],10) == 30
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# print(rod_cutting([],0))
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if __name__ == '__main__':
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main()
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