Creating a Python Function to Generate Combinations of 5 and 7 Summing to a Specific Amount

Develop a Python method change(amount) that for any integer amount in the range from 24 to 1000 returns a list consisting of numbers 5 and 7 only, such that their sum is equal to amount. For example, change(28) may return [7, 7, 7, 7], while change(49) may return [7, 7, 7, 7, 7, 7, 7] or [5, 5, 5, 5, 5, 5, 5, 7, 7] or [7, 5, 5, 5, 5, 5, 5, 5, 7].

To solve this quiz, implement the method change(amount) on your machine, test it on several inputs, and then paste your code in the field below and press the submit quiz button. Your submission should contain the change method only (in particular, make sure to remove all print statements).

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Solution)

def change(amount):
    # Check if the amount is within the valid range
    if amount < 24 or amount > 1000:
        return []

    # Try different combinations of 7s and 5s
    for num_sevens in range(amount // 7, -1, -1):
        remainder = amount - num_sevens * 7
        if remainder % 5 == 0:
            num_fives = remainder // 5
            return [7] * num_sevens + [5] * num_fives

    # If no combination is found, return an empty list
    return []

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1. amount // 7: This is floor division, which divides amount by 7 and rounds down to the nearest whole number. It calculates the maximum number of 7s that can fit into amount.
2. range(amount // 7, -1, -1): This creates a sequence of numbers starting from amount // 7 and ending at -1 (but not including -1), decrementing by 1 each time. Essentially, it counts backwards from the maximum number of 7s possible.
   • range(amount // 7, -1, -1) generates a sequence of numbers starting from the maximum number of 7s that can fit into amount and counting down to 0. For example, if amount is 28, amount // 7 is 4, so the range would be range(4, -1, -1), which generates the sequence [4, 3, 2, 1, 0].

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