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* Tried new TESTS for the binomial_coefficient * Fix the tests request * Update binomial_coefficient.py * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * Update binomial_coefficient.py --------- Co-authored-by: Christian Clauss <cclauss@me.com> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
63 lines
1.6 KiB
Python
63 lines
1.6 KiB
Python
def binomial_coefficient(n: int, r: int) -> int:
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"""
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Find binomial coefficient using Pascal's triangle.
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Calculate C(n, r) using Pascal's triangle.
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:param n: The total number of items.
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:param r: The number of items to choose.
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:return: The binomial coefficient C(n, r).
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>>> binomial_coefficient(10, 5)
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252
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>>> binomial_coefficient(10, 0)
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1
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>>> binomial_coefficient(0, 10)
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1
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>>> binomial_coefficient(10, 10)
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1
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>>> binomial_coefficient(5, 2)
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10
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>>> binomial_coefficient(5, 6)
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0
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>>> binomial_coefficient(3, 5)
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0
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>>> binomial_coefficient(-2, 3)
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Traceback (most recent call last):
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...
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ValueError: n and r must be non-negative integers
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>>> binomial_coefficient(5, -1)
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Traceback (most recent call last):
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...
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ValueError: n and r must be non-negative integers
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>>> binomial_coefficient(10.1, 5)
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Traceback (most recent call last):
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...
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TypeError: 'float' object cannot be interpreted as an integer
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>>> binomial_coefficient(10, 5.1)
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Traceback (most recent call last):
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...
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TypeError: 'float' object cannot be interpreted as an integer
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"""
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if n < 0 or r < 0:
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raise ValueError("n and r must be non-negative integers")
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if 0 in (n, r):
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return 1
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c = [0 for i in range(r + 1)]
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# nc0 = 1
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c[0] = 1
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for i in range(1, n + 1):
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# to compute current row from previous row.
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j = min(i, r)
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while j > 0:
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c[j] += c[j - 1]
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j -= 1
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return c[r]
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if __name__ == "__main__":
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from doctest import testmod
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testmod()
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print(binomial_coefficient(n=10, r=5))
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