104 lines
1.5 KiB
Ruby
104 lines
1.5 KiB
Ruby
# When done, submit this entire file to the autograder.
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# Part 1
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def sum arr
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# YOUR CODE HERE
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sum = 0
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arr.each do |i|
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sum += i
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end
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return sum
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end
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def max_2_sum arr
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# YOUR CODE HERE
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if arr.size == 0
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return 0
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elsif arr.size == 1
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return arr[0]
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else
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sum = 0
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sum += arr.max
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arr.delete_at arr.index(sum)
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sum += arr.max
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return sum
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end
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end
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def sum_to_n? arr, n
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# YOUR CODE HERE
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if arr.size < 2
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return false
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end
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arr.each_with_index do |first_number, i|
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j = i + 1
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while j < arr.size
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if first_number + arr[j] == n
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return true
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end
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j += 1
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end
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end
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return false
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end
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# Part 2
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def hello(name)
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# YOUR CODE HERE
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"Hello, " + name
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end
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def starts_with_consonant? s
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# YOUR CODE HERE
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if /^[^aeiouAEIOU]/ =~ s and /^[a-zA-Z]/ =~ s # 必须不能一以原因以原音字母开头，而且必须以字母开头
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return true
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end
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return false
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end
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def binary_multiple_of_4? s
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# YOUR CODE HERE
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if /[^01]/ =~ s # 判断是否有效
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return false
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end
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if s.size == 0
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return false
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end
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if s.size == 1
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return s == "0"
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end
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if s.size == 2
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return s == "00"
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end
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if s[-2..-1].to_s.include?('1')
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return false
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else
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return true
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end
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end
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# Part 3
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class BookInStock
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# YOUR CODE HERE
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def initialize(isbn, price)
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if isbn.empty? or price <= 0
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raise ArgumentError
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end
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@isbn = isbn
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@price = price
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end
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attr_accessor :isbn
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attr_accessor :price
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def price_as_string
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format('$%.2f', @price)
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end
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end
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