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 Go (1.14.1) (judge verdict: Wrong Answer)

package main

import (
	"bufio"
	"bytes"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"runtime"
	"runtime/pprof"
	"strconv"
)

var DEBUG = true

var cpuprofile = flag.String("cpuprofile", "", "write cpu profile")

func main() {
	flag.Parse()

	if *cpuprofile != "" {
		f, err := os.Create(*cpuprofile)
		if err != nil {
			log.Fatal(err)
		}
		pprof.StartCPUProfile(f)
		defer pprof.StopCPUProfile()
	}

	defer Flush()
	N := readi()
	Q := readi()

	z := U(0)

	b := NewFenwickTree(N, &z)
	for i := 0; i < N; i++ {
		v := readi()
		u := U(v)
		b.Add(i, &u)
	}
	for q := 0; q < Q; q++ {
		t := readi()
		x := readi()
		y := readi()
		if t == 0 {
			add(b, x, y)
		} else {
			println(sum(b, x, y))
		}
	}

}

func add(ft *FenwickTree, p, x int) {
	u := U(x)
	ft.Add(p, &u)
}

func sum(ft *FenwickTree, l, r int) int {
	v := ft.Sum(l, r).(*U)
	return int(*v)
}

type U int

func (u *U) Add(x FenwickTreeUnit) {
	ux := x.(*U)
	*u = *u + *ux
}

func (u *U) Sub(x FenwickTreeUnit) {
	ux := x.(*U)
	*u = *u - *ux
}

type FenwickTreeUnit interface {
	Add(x FenwickTreeUnit)
	Sub(x FenwickTreeUnit)
}

// BIT represents the Binary Indexed Tree
type FenwickTree struct {
	n    int
	data []FenwickTreeUnit
	z    FenwickTreeUnit
}

// NewBIT returns the pointer to a FenwickTree for the slice.
func NewFenwickTree(n int, zeroValue FenwickTreeUnit) *FenwickTree {
	ft := &FenwickTree{
		n:    n,
		data: make([]FenwickTreeUnit, n),
		z:    zeroValue,
	}

	for i := range ft.data {
		ft.data[i] = ft.z
	}

	return ft
}

func (ft *FenwickTree) assert(exp bool) {
	if exp {
		return
	}

	pc, file, line, ok := runtime.Caller(1)
	if !ok {
		panic("ASSERT!: unknown position")
	}
	msg := fmt.Sprintf("ASSERT!: @0x%x %s[%d]", pc, file, line)
	panic(msg)
}

func (ft *FenwickTree) sum(r int) FenwickTreeUnit {
	s := ft.z
	for r > 0 {
		s.Add(ft.data[r-1])
		r -= r & -r
	}
	return s
}

func (ft *FenwickTree) Sum(l, r int) FenwickTreeUnit {
	ft.assert(0 <= l && l <= r && r <= ft.n)
	x := ft.sum(r)
	x.Sub(ft.sum(l))
	return x
}

func (ft *FenwickTree) Add(p int, x FenwickTreeUnit) {
	ft.assert(0 <= p && p < ft.n)
	p++
	for p <= ft.n {
		ft.data[p-1].Add(x)
		p += p & -p
	}
}

// -----------------------------------------------------------------------------

// IO helper functions

// Returns next token from input.  It must be initialized by SetInput()
// before the first call.
var nextToken func() ([]byte, error)
var nextLine func() ([]byte, error)

// Holds a buffer for output.  It must be initialized by SetOutput().
// All IO fucntions (read*() and [e]print*()) should write to OutputWriter
// instead of this.
var OutputBuffer *bufio.Writer

// Holds an io.Writer.  It must be initialized by SetOutput()
var OutputWriter io.Writer

// Set IO functions for interactive input/output.
func SetInteractive(w io.Writer, r io.Reader) {
	SetUnbefferedInput(r)
	OutputBuffer = nil
	OutputWriter = w
}

// Setup OutputBuffer and OutputWriter.
func SetOutput(w io.Writer) {
	OutputBuffer = bufio.NewWriter(w)
	OutputWriter = OutputBuffer
}

// Flushes OutputBuffer
func Flush() {
	if OutputBuffer != nil {
		OutputBuffer.Flush()
	}
}

// Returns true if c is a white space
func IsSpace(c byte) bool {
	switch c {
	case '\t', '\n', '\v', '\f', '\r', ' ':
		return true
	}
	return false
}

func IsNewLine(c byte) bool {
	switch c {
	case '\n', '\r':
		return true
	}
	return false
}

// Setup nextToken with input buffer.
func SetInput(r io.Reader) {
	buf := new(bytes.Buffer)
	var b []byte

	var i int
	rest := func() ([]byte, error) {
		for i < len(b) && IsSpace(b[i]) {
			i++
		}
		if i == len(b) {
			return nil, io.ErrUnexpectedEOF
		}
		j := i
		for i < len(b) && !IsSpace(b[i]) {
			i++
		}
		return b[j:i], nil
	}
	initial := func() ([]byte, error) {
		io.Copy(buf, r)
		b = buf.Bytes()
		nextToken = rest
		return rest()
	}
	nextToken = initial

	restLn := func() ([]byte, error) {
		for i < len(b) && IsNewLine(b[i]) {
			i++
		}
		if i == len(b) {
			return nil, io.ErrUnexpectedEOF
		}
		j := i
		for i < len(b) && !IsNewLine(b[i]) {
			i++
		}
		return b[j:i], nil
	}

	initialLn := func() ([]byte, error) {
		io.Copy(buf, r)
		b = buf.Bytes()
		nextLine = restLn
		return restLn()
	}
	nextLine = initialLn
}

// Setup nextToken without input buffer.
func SetUnbefferedInput(r io.Reader) {
	buf := bufio.NewReader(r)
	var b []byte

	var i int
	nextToken = func() ([]byte, error) {
		var err error
		if i == len(b) {
			b, err = buf.ReadBytes('\n')
			if err != nil {
				return nil, err
			}
			i = 0
			j := len(b) - 1
			for 0 <= j && IsSpace(b[j]) {
				j--
			}
			b = b[0 : j+1]
		}
		for i < len(b) && IsSpace(b[i]) {
			i++
		}
		j := i
		for i < len(b) && !IsSpace(b[i]) {
			i++
		}
		if i == j {
			return nil, io.ErrUnexpectedEOF
		}
		return b[j:i], nil
	}
}

// -----------------------------------------------------------------------------

// IO functions

// Reads next token and return it as []byte
func readb() []byte {
	b, err := nextToken()
	if err != nil {
		panic(err)
	}
	return b[:len(b):len(b)]
}

func readberr() ([]byte, error) {
	b, err := nextToken()
	return b[:len(b):len(b)], err
}

// Reads next token and return it as string
func reads() string {
	return string(readb())
}

func readserr() (string, error) {
	b, err := readberr()
	return string(b), err
}

// Read next line as []byte.  Trailing '\n' will not be included.
// See also comments on readb()
func readbln() []byte {
	b, err := nextLine()
	if err != nil {
		panic(err)
	}
	return b[:len(b):len(b)]
}

func readblnerr() ([]byte, error) {
	b, err := nextLine()
	return b[:len(b):len(b)], err
}

// Read next line as string
func readsln() string {
	return string(readbln())
}

func readslnerr() (string, error) {
	b, err := readblnerr()
	return string(b), err
}

// Reads next token and return it as int64
func readll() int64 {
	i, err := strconv.ParseInt(reads(), 10, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func readllerr() (int64, error) {
	s, err := readserr()
	if err != nil {
		return 0, fmt.Errorf("reading string: %w", err)
	}

	i, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		return 0, fmt.Errorf("parsing int: %w", err)
	}

	return i, nil
}

// Reads next token and return it as int
func readi() int {
	return int(readll())
}

func readierr() (int, error) {
	i, err := readllerr()
	return int(i), err
}

// Reads next token and return it as float64
func readf() float64 {
	f, err := strconv.ParseFloat(reads(), 64)
	if err != nil {
		panic(err.Error())
	}
	return f
}

func readferr() (float64, error) {
	s, err := readserr()
	if err != nil {
		return 0, fmt.Errorf("reading string: %w", err)
	}

	f, err := strconv.ParseFloat(s, 64)
	if err != nil {
		return 0, fmt.Errorf("parsing float: %w", err)
	}

	return f, nil
}

// Write args to OutputWriter with the format f
func printf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(OutputWriter, f, args...)
}

// Write args to OutputWriter without format
func println(args ...interface{}) (int, error) {
	return fmt.Fprintln(OutputWriter, args...)
}

// Write args to stderr with the format f
func eprintf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(os.Stderr, f, args...)
}

// Write args to stderr without format
func eprintln(args ...interface{}) (int, error) {
	return fmt.Fprintln(os.Stderr, args...)
}

func dbgf(f string, args ...interface{}) {
	if !DEBUG {
		return
	}
	fmt.Fprintf(os.Stderr, f, args...)
}

func dbg(args ...interface{}) {
	if !DEBUG {
		return
	}
	fmt.Fprintln(os.Stderr, args...)
}

// -----------------------------------------------------------------------------

// Utilities

func sumSlice(a []int) int {
	var res int
	for _, v := range a {
		res += v
	}
	return res
}

func sumSlicell(a []int64) int64 {
	var res int64
	for _, v := range a {
		res += v
	}
	return res
}

func readInts(N int) (int, []int) {
	if N == 0 {
		N = readi()
	}
	a := make([]int, N)
	for i := range a {
		a[i] = readi()
	}
	return N, a
}

func readIntsll(N int) (int, []int64) {
	if N == 0 {
		N = readi()
	}
	a := make([]int64, N)
	for i := range a {
		a[i] = readll()
	}
	return N, a
}

// -----------------------------------------------------------------------------

// Simple math functions

const (
	// big prime
	INF  = 1000000007
	INF2 = 1000000009
	INF3 = 998244353
)

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func minll(a, b int64) int64 {
	if a < b {
		return a
	}
	return b
}

func minf(a, b float64) float64 {
	if a < b {
		return a
	}
	return b
}

func max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func maxll(a, b int64) int64 {
	if a < b {
		return b
	}
	return a
}

func maxf(a, b float64) float64 {
	if a < b {
		return b
	}
	return a
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func absll(a int64) int64 {
	if a < 0 {
		return -a
	}
	return a
}

func absf(a float64) float64 {
	if a < 0 {
		return -a
	}
	return a
}

// egcd(a, b) returns d, x, y:
//   d is gcd(a,b)
//   x, y are  integers that satisfy ax + by = d
func egcd(a, b int) (int, int, int) {
	if b == 0 {
		return a, 1, 0
	}
	d, x, y := egcd(b, a%b)
	return d, y, x - a/b*y
}

func egcdll(a, b int64) (int64, int64, int64) {
	if b == 0 {
		return a, 1, 0
	}
	d, x, y := egcdll(b, a%b)
	return d, y, x - a/b*y
}

func gcd(a, b int) int {
	d, _, _ := egcd(a, b)
	return d
}

func gcdll(a, b int64) int64 {
	d, _, _ := egcdll(a, b)
	return d
}

// set up IO functions
func init() {
	// for non-interactive
	SetInput(os.Stdin)
	SetOutput(os.Stdout)

	// Enable below when interactive.  Its ok to leave above intact.
	// SetInteractive(os.Stdout, os.Stdin)
}