TS's memorandom

答えは287桁目になるはずで、その値は0726024914。テキストの円周率表とrubyで簡単なスクリプトを作って力技で解いてみました (^^ゞ 以下はコード

def is_date(str)
  days = [31,29,31,30,31,30,31,31,30,31,30,31]
  return false if (str.length != 10)
  month = str[0,2].to_i
  day = str[2,2].to_i
  hour = str[4,2].to_i
  minute = str[6,2].to_i
  second = str[8,2].to_i
  return false if (month < 1 || month > 12)
  return false if (day < 1 ||  day > days[month-1])
  return false if (hour < 0 || hour > 23)
  return false if (minute < 0 || minute > 59)
  return false if (second < 0 || second > 59)
  true
end

begin
  if ARGV.length != 0
    max = ARGV[0].to_i
  end
rescue
  max = 1000
end
fp = open("pi104.txt", "r")
pi=''
n=0
fp.each_byte { |c|
  break if n > max
  next if (c.chr < '0' || c.chr > '9')
  pi += c.chr if n > 0
  n += 1
}
pos = 0
while (current = (/[01]/ =~ pi)) do
  pos += current+1
  str = pi[current,10]
  pi = pi[current+1 .. -1]
  puts "match:#pos #{current} #{str}"
  break if (is_date(str))
end
if (current)
  puts "#{pos} #{str}"
else
  puts "no date value"
end