Python - Designing Algorithms - list, index, minimum value, maximum value, for loop, one pass

Practical Programming
楽天ブックス 紀伊国屋書店

開発環境

• macOS Catalina - Apple (OS)
• Emacs (Text Editor)
• Windows 10 Pro (OS)
• Visual Studio Code (Text Editor)
• Python 3.8 (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3.6 (Paul Gries(著)、Jennifer Campbell(著)、Jason Montojo(著)、Pragmatic Bookshelf)のChapter 12(Designing Algorithms)、Exercise 2の解答を求めてみる。

コード

#!/usr/bin/env python3
from unittest import TestCase, main
from typing import List, Tuple

print('2-a, b, c.')


class TestMinIndex(TestCase):
    def test_1(self):
        self.assertEqual(min_find([1]), (1, 0))

    def test_2(self):
        self.assertEqual(min_find([1, 1]), (1, 0))

    def test_3(self):
        self.assertEqual(min_find([2, 4, 6, 8, 1, 3, 5, 7]), (1, 4))


class TestMaxIndex(TestCase):
    def test_1(self):
        self.assertEqual(max_find([1]), (1, 0))

    def test_2(self):
        self.assertEqual(max_find([1, 1]), (1, 0))

    def test_3(self):
        self.assertEqual(max_find([2, 4, 6, 8, 1, 3, 5, 7]), (8, 3))


class TestMinOrMaxIndex(TestCase):
    def test_1(self):
        self.assertEqual(min_find([1]), (1, 0))

    def test_2(self):
        self.assertEqual(min_find([1, 1]), (1, 0))

    def test_3(self):
        self.assertEqual(min_find([2, 4, 6, 8, 1, 3, 5, 7]), (1, 4))

    def test_max1(self):
        self.assertEqual(min_or_max_index([1], False), (1, 0))

    def test_max2(self):
        self.assertEqual(min_or_max_index([1, 1], False), (1, 0))

    def test_max3(self):
        self.assertEqual(min_or_max_index([2, 4, 6, 8, 1, 3, 5, 7], False),
                         (8, 3))
# b.


def min_find(nums: List[int]) -> Tuple[int, int]:
    # a. for loop
    minimum_value = nums[0]
    index = 0
    for i, num in enumerate(nums[1:], 1):
        if num < minimum_value:
            minimum_value = num
            index = i
    return minimum_value, index

# c.


def max_find(nums: List[int]) -> Tuple[int, int]:
    maximum_value = nums[0]
    index = 0
    for i, num in enumerate(nums[1:], 1):
        if num > maximum_value:
            maximum_value = num
            index = i
    return maximum_value, index


def min_or_max_index(nums: List[int], is_min=True) -> Tuple[int, int]:
    if is_min:
        return min_find(nums)
    return max_find(nums)


if __name__ == "__main__":
    main()

入出力結果(Zsh、PowerShell、Terminal、Jupyter(IPython))

% ./sample2.py -v
2-a, b, c.
test_1 (__main__.TestMaxIndex) ... ok
test_2 (__main__.TestMaxIndex) ... ok
test_3 (__main__.TestMaxIndex) ... ok
test_1 (__main__.TestMinIndex) ... ok
test_2 (__main__.TestMinIndex) ... ok
test_3 (__main__.TestMinIndex) ... ok
test_1 (__main__.TestMinOrMaxIndex) ... ok
test_2 (__main__.TestMinOrMaxIndex) ... ok
test_3 (__main__.TestMinOrMaxIndex) ... ok
test_max1 (__main__.TestMinOrMaxIndex) ... ok
test_max2 (__main__.TestMinOrMaxIndex) ... ok
test_max3 (__main__.TestMinOrMaxIndex) ... ok

----------------------------------------------------------------------
Ran 12 tests in 0.001s

OK
%