选择不同子字符串覆盖的字符串

Question

我想选择具有以下属性的一组子字符串覆盖的字符串部分：

• 它们属于原始字符串。
• 它们可能有不同的长度和位置。
• 它们可以重叠。
• 它们可能不会按照它们在原始字符串中出现的顺序排列。

例如：

string = "MGLSDGEWQQVLNVWGKVEADIAGHGQEVLIHSKHPGDFGADAQGAMTKALELFRNDIAAKYKELGFQG"
substring1 = "HPGDFGADAQGAMTKALELFR"
substring2 = "GEWQQVLNVWGK"
substringn = "ALELFRNDIAAKYK"

我想得到：

coverage = "MGLSD<b>GEWQQVLNVWGK</b>VEADIAGHGQEVLIHSK<b>HPGDFGADAQGAMTKALELFRNDIAAKYK</b>ELGFQG"

我试图提取字符串中子字符串的位置，如下所示：

substrings_array.each do |substring|
  start_pos = string.index substring
  end_pos = string.length - (string.reverse.index(substring.reverse) )
end

这样，我得到每个子字符串的开始和结束位置。我怎样才能将它们全部合并，特别是考虑到它们可能重叠并以不同的顺序出现？这甚至是一个好策略吗？

Answer 1

这应该有效（不漂亮，但有效）：

string = "MGLSDGEWQQVLNVWGKVEADIAGHGQEVLIHSKHPGDFGADAQGAMTKALELFRNDIAAKYKELGFQG"
substring1 = "HPGDFGADAQGAMTKALELFR"
substring2 = "GEWQQVLNVWGK"
substring3 = "ALELFRNDIAAKYK"

substrings = [substring1, substring2, substring3]

overlapping_indexes = substrings.map do |substring|
  start_pos = string.index substring
  end_pos = start_pos + substring.length
  (start_pos..end_pos)
end

# the following 3 methods are from Wayne Conrad in this question: http://stackoverflow.com/questions/6017523/how-to-combine-overlapping-time-ranges-time-ranges-union

def ranges_overlap?(a, b)
  a.include?(b.begin) || b.include?(a.begin)
end

def merge_ranges(a, b)
  [a.begin, b.begin].min..[a.end, b.end].max
end

def merge_overlapping_ranges(ranges)
  ranges.sort_by(&:begin).inject([]) do |ranges, range|
    if !ranges.empty? && ranges_overlap?(ranges.last, range)
      ranges[0...-1] + [merge_ranges(ranges.last, range)]
    else
      ranges + [range]
    end
  end
end

indexes = merge_overlapping_ranges(overlapping_indexes)

x = "<b>"
y = "</b>"
offset = 0

indexes.each do |index|
  string.insert(index.begin + offset, x)
  offset += x.length
  string.insert(index.end + offset, y)
  offset += y.length
end

p string