45 lines
1 KiB
Ruby
45 lines
1 KiB
Ruby
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# @param {String} s
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# @return {Integer}
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def length_of_longest_substring(s)
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# Create a hash map to save
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# the position of every symbol
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indexes = Hash.new(-1)
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# Start and end of the current sequence s[i...j]
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i = 0
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j = 0
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# Result will be stored here
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maxlen = 0
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while i < s.length
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# While we haven't reached the end of the string
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# and haven't seen current character before
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while j < s.length && indexes[s[j]] == -1
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# Save character's position
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indexes[s[j]] = j
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# Move to the next character
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j += 1
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end
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# We just reached the end of the string
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# and we will never find a longer substring.
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return [maxlen, j - i].max if j == s.length
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# It's not the end of the string,
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# repeated character found.
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# Save max length and set "i"
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# to the character right after the first repeated.
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maxlen = [maxlen, j - i].max
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new_i = indexes[s[j]] + 1
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while i != new_i
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indexes[s[i]] = -1
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i += 1
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end
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indexes[s[j]] = j
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j += 1
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end
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maxlen
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end
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