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* Add doctests for sum_of_arithmetic_series function * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: Christian Clauss <cclauss@me.com>
43 lines
1.3 KiB
Python
43 lines
1.3 KiB
Python
# Reeka
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def sum_of_ap_series(a: int, d: int, n: int) -> int:
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"""
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Calculates the sum of the first 'n' terms of an arithmetic progression (AP)
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series with the first term 'a' and common difference 'd'.
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Parameters:
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a (int): The first term of the AP.
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d (int): The common difference between terms.
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n (int): The number of terms to sum.
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Returns:
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int: The sum of the first 'n' terms of the AP.
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Examples:
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>>> sum_of_ap_series(1, 1, 5) # Sum of first 5 natural numbers
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15
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>>> sum_of_ap_series(2, 3, 4) # Sum of 2, 5, 8, 11
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26
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>>> sum_of_ap_series(5, 0, 3) # Sum of 5, 5, 5
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15
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>>> sum_of_ap_series(1, 2, 1) # Single term AP series
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1
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>>> sum_of_ap_series(1, -1, 5) # Decreasing AP series
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-5
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>>> sum_of_ap_series(1, 1, -5) # Negative 'n' should raise an error
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Traceback (most recent call last):
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...
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ValueError: Number of terms 'n' must be a positive integer
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>>> sum_of_ap_series(1, 1, 0) # Zero terms should also raise an error
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Traceback (most recent call last):
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...
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ValueError: Number of terms 'n' must be a positive integer
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"""
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if n <= 0:
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raise ValueError("Number of terms 'n' must be a positive integer")
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# Formula for the sum of an AP series: S_n = n/2 * (2a + (n-1) * d)
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return n * (2 * a + (n - 1) * d) // 2
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# Reeka
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