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, 7 years ago→Generate a Regular Expression for a Range of Integers
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=== Generate a Regular Expression for a Range of Integers ===
Write a function that, given the integers 0 <= ''min'' < = ''max'', returns a regular expression that will match the decimal representation of any integer in the range [''min'', ''max'']. You may assume there are no thousand-separators, leading 0's, or other problematic characters in the string to be processed. You may also assume the caller of your function will prepend/append appropriate anchors (e.g., ^, $, or \b) depending on need, so don't include them. Don't use \d as an alias for [0-9] since \d can match weird unicode characters on some systems.
Example:
min = 1
max = 31
possible result = [1-9]|[1-2][0-9]|3[0-1]
possible result = [1-9]|[12][0-9]|3[01]
Example:
min = 91
max = 417
possible result = 9[1-9]|[1-3][0-9]{2}|4(0[0-9]|1[0-7])
possible result = 9[1-9]|[1-3][0-9][0-9]|4(0[0-9]|1[0-7])
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