21/07/01 19:49:58.87 rhoqKmqn.net
>>36 Ruby
str = '2021 7 0'
y, m, s = str.scan( /\d+/ ).map( &:to_i )
( '日月火水木金土'.chars.rotate(s) + [' '] * (( Time.new( y, m, 1 ).wday - s ) % 7) + (1 .. [31, 30, 29, 28].find{|d| Time.new( y, m, d ).month == m }).to_a.map{|d| '%2d' % d } ).flatten.each_slice(7){|w| puts w * ' ' }