AtCoder ARC #075 / ABC #063

arc075-a.rb

a, b = gets.chomp.split(" ").map(&:to_i)
if a + b >= 10 then
  puts "error"
else
  puts a + b
end

arc075-b.rb

s = gets.chomp.split("")
n = s.length
if s.uniq.length == n then
  puts "yes"
else
  puts "no"
end

arc075-c.rb

n = gets.chomp.to_i
s = []
ssum = 0
n.times do
  x = gets.chomp.to_i
  ssum += x
  s << x
end

s.sort!
if ssum % 10 == 0 then
  while x = s.shift
    if x % 10 != 0 then
      puts ssum - x
      exit
    end
  end
  puts 0
else
  puts ssum
end

arc075-d.rb

n, $a, $b = gets.chomp.split(" ").map(&:to_i)

$h = []
n.times do
  $h << gets.chomp.to_f
end

def enough(i)
  ret = $h.map{|x| ([(x - i * $b), 0].max / ($a - $b)).ceil}.inject(:+)
  return ret <= i
end

puts (1..$h.max.to_i).bsearch{|i| enough(i)}

arc075-e.rb

class BIT
  attr_reader :bit
  def initialize(n)
    @n = n
    @bit = Array.new(@n + 1, 0)
  end
  def sum(i)
    s = 0
    while i > 0
      s +=  @bit[i]
      i -= i & -i
    end
    return s
  end
  def add(i, x)
    i += 1
    while i <= @n
      @bit[i] += x
      i += i & -i
    end
  end
end

n, k = gets.chomp.split(" ").map(&:to_i)
a = [0]
a += readlines.map{|x| x.chomp.to_i - k}

b = [0]
n.times do |i|
  b << b[i] + a[i+1]
end

b_s = b.sort
c = b.map{|e| b_s.bsearch_index{|x| x >= e}}

bit = BIT.new(n+1)

ans = 0
c.each do |i|
  ans += bit.sum(i+1)
  bit.add(i, 1)
end
puts ans