Problem:
Score : 100 points

Problem Statement

You are given an array a_0, a_1, ..., a_{N-1} of length N. Process Q queries of the following types.

0 p x: a_p \gets a_p + x

1 l r: Print \sum_{i = l}^{r - 1}{a_i}.

Constraints

1 \leq N, Q \leq 500,000

0 \leq a_i, x \leq 10^9

0 \leq p < N

0 \leq l_i < r_i \leq N

All values in Input are integer.

Input

Input is given from Standard Input in the following format:

N Q
a_0 a_1 ... a_{N - 1}
\textrm{Query}_0
\textrm{Query}_1
:
\textrm{Query}_{Q - 1}

Output

For each query of the latter type, print the answer.

Sample Input 1

5 5
1 2 3 4 5
1 0 5
1 2 4
0 3 10
1 0 5
1 0 3

Sample Output 1

15
7
25
6

Solution in Ruby (2.7.1) (judge verdict: Accepted)

# frozen_string_literal: true

# Fenwick Tree
class FenwickTree
  def initialize(arg)
    case arg
    when Array
      @size = arg.size
      @data = Array.new(@size + 1) { 0 }
      arg.each.with_index(1) { |e, i| add(i, e) }
    when Integer
      @size = arg
      @data = Array.new(@size + 1) { 0 }
    else
      raise ArgumentError
    end
  end

  def add(i, x)
    while i <= @size
      @data[i] += x
      i += (i & -i)
    end
  end

  def sum(l, r)
    _sum(r) - _sum(l)
  end

  def _sum(i)
    res = 0
    while i > 0
      res += @data[i]
      i -= (i & -i)
    end
    res
  end
end

FeTree            = FenwickTree
BinaryIndexedTree = FenwickTree

n, q = gets.split.map(&:to_i)
a    = gets.split.map(&:to_i)
 
ft = FeTree.new(a)
 
q.times do
  t, u, v = gets.split.map(&:to_i)
 
  if t == 0
    ft.add(u + 1, v)
  else
    puts ft.sum(u, v)
  end
end