Code Festival 予選C

code-fes-2016-qual-c-a.rb

s = gets.chomp
c = s.index("C")
ret = false
if !c.nil? then
  f = s[c..(s.length-1)].index("F")
  if !f.nil?
    ret = true
  end
end
if ret then
  puts "Yes"
else
  puts "No"
end

code-fes-2016-qual-c-b.rb

k, t = gets.chomp.split(" ").map(&:to_i)
aa = gets.chomp.split(" ").map(&:to_i).sort
aamax = aa.last
puts [aamax - 1 - (k - aamax), 0].max

code-fes-2016-qual-c-c.rb

n = gets.chomp.to_i
tt = gets.chomp.split(" ").map(&:to_i)
aa = gets.chomp.split(" ").map(&:to_i)
htt = Array.new(n, nil)
tt.each_with_index do |e, i|
  if i == 0 || tt[i-1] < e then  
    htt[i] = e
  end
end
haa = Array.new(n, nil)
aa.each_with_index do |e, i|
  if i == (n - 1) || aa[i + 1] < e then
    haa[i] = e
  end
end
ret = 1
tt.zip(aa).each_with_index do |e, i|
  if haa[i] && e[0] < haa[i] then
    puts 0; exit
  elsif htt[i] && e[1] < htt[i] then
    puts 0; exit
  elsif htt[i] || haa[i] then
    next
  end
  ret *= e.min
  ret %= (10**9 + 7)
end
puts ret