algo scan helper

scanner.go

// https://gist.github.com/romsar/6f11c51ec35a4a982eed786da958aecc
import (
	"bufio"
	"os"
	"strconv"
	"strings"
)

type Scanner struct {
	s *bufio.Scanner
}

func NewScanner() Scanner {
	const maxCapacity = 4 * 1024 * 1024
	buf := make([]byte, maxCapacity)
	s := bufio.NewScanner(os.Stdin)
	s.Buffer(buf, maxCapacity)

	return Scanner{s: s}
}

func (s *Scanner) String() string {
	return s.scan()
}

func (s *Scanner) StringSlice() []string {
	return s.scanSlice()
}

func (s *Scanner) Bool() bool {
	return toBool(s.scan())
}

func (s *Scanner) BoolSlice() []bool {
	return toSlice(s.scanSlice(), toBool)
}

func toBool(str string) bool {
	b, _ := strconv.ParseBool(str)
	return b
}

func (s *Scanner) Int() int {
	return toInt(s.scan())
}

func (s *Scanner) IntSlice() []int {
	return toSlice(s.scanSlice(), toInt)
}

func toInt(str string) int {
	num, _ := strconv.Atoi(str)
	return num
}

func (s *Scanner) Int8() int8 {
	return toInt8(s.scan())
}

func (s *Scanner) Int8Slice() []int8 {
	return toSlice(s.scanSlice(), toInt8)
}

func toInt8(str string) int8 {
	i, _ := strconv.ParseInt(str, 10, 8)
	return int8(i)
}

func (s *Scanner) Int16() int16 {
	return toInt16(s.scan())
}

func (s *Scanner) Int16Slice() []int16 {
	return toSlice(s.scanSlice(), toInt16)
}

func toInt16(str string) int16 {
	i, _ := strconv.ParseInt(str, 10, 16)
	return int16(i)
}

func (s *Scanner) Int32() int32 {
	return toInt32(s.scan())
}

func (s *Scanner) Int32Slice() []int32 {
	return toSlice(s.scanSlice(), toInt32)
}

func toInt32(str string) int32 {
	i, _ := strconv.ParseInt(str, 10, 32)
	return int32(i)
}

func (s *Scanner) Int64() int64 {
	return toInt64(s.scan())
}

func (s *Scanner) Int64Slice() []int64 {
	return toSlice(s.scanSlice(), toInt64)
}

func toInt64(str string) int64 {
	i, _ := strconv.ParseInt(str, 10, 64)
	return i
}

func (s *Scanner) Float32() float32 {
	return toFloat32(s.scan())
}

func (s *Scanner) Float32Slice() []float32 {
	return toSlice(s.scanSlice(), toFloat32)
}

func toFloat32(str string) float32 {
	f, _ := strconv.ParseFloat(str, 32)
	return float32(f)
}

func (s *Scanner) Float64() float64 {
	return toFloat64(s.scan())
}

func (s *Scanner) Float64Slice() []float64 {
	return toSlice(s.scanSlice(), toFloat64)
}

func toFloat64(str string) float64 {
	f, _ := strconv.ParseFloat(str, 64)
	return f
}

func (s *Scanner) scan() string {
	s.s.Scan()
	return s.s.Text()
}

func (s *Scanner) scanSlice() []string {
	s.s.Scan()

	return strings.Split(s.s.Text(), " ")
}

func toSlice[T any](strs []string, f func(string) T) []T {
	res := make([]T, len(strs))
	for i, str := range strs {
		res[i] = f(str)
	}
	return res
}

Compact version:

// https://gist.github.com/romsar/6f11c51ec35a4a982eed786da958aecc#gistcomment-4957930
import (
	"bufio"
	"os"
	"strconv"
	"strings"
)

type Scanner struct {
	s *bufio.Scanner
}

func NewScanner() Scanner {
	const maxCapacity = 4 * 1024 * 1024
	buf := make([]byte, maxCapacity)
	s := bufio.NewScanner(os.Stdin)
	s.Buffer(buf, maxCapacity)

	return Scanner{s: s}
}

func (s *Scanner) String() string        { return s.scan() }
func (s *Scanner) StringSlice() []string { return s.scanSlice() }

func (s *Scanner) Int() int        { return toInt(s.scan()) }
func (s *Scanner) IntSlice() []int { return toSlice(s.scanSlice(), toInt) }
func toInt(str string) int         { num, _ := strconv.Atoi(str); return num }

func (s *Scanner) Float64() float64        { return toFloat64(s.scan()) }
func (s *Scanner) Float64Slice() []float64 { return toSlice(s.scanSlice(), toFloat64) }
func toFloat64(str string) float64         { f, _ := strconv.ParseFloat(str, 64); return f }

func (s *Scanner) scan() string        { s.s.Scan(); return s.s.Text() }
func (s *Scanner) scanSlice() []string { s.s.Scan(); return strings.Split(s.s.Text(), " ") }

func toSlice[T any](strs []string, f func(string) T) []T {
	res := make([]T, len(strs))
	for i, str := range strs {
		res[i] = f(str)
	}
	return res
}