AtCoder AGC #023 A

agc023-a.rb

n = gets.chomp.to_i
a = gets.chomp.split(" ").map(&:to_i)
s = [0]
n.times do |i|
  s[i+1] = s[i] + a[i]
end
h = Hash.new(0)
s.each do |i|
  h[i] += 1
end

ans = 0

h.each do |k, v|
  if v == 1
    next
  elsif v == 2
    ans += 1
  else
    ans += (v * (v - 1) / 2)
  end
end

puts ans