Submission #1662128

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Source Code Expand

package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"strconv"
)

func f(b, n int) int {
	if n < b {
		return n
	}
	return f(b, n/b) + n%b
}

func main() {
	scn := newScanner()
	n := scn.nextInt()
	s := scn.nextInt()
	ans := -1
	if n < s {
		ans = -1
	} else if n == s {
		ans = n + 1
	} else {
		for i := 2; i*i <= n; i++ {
			if f(i, n) == s {
				ans = i
				break
			}
		}
		if ans == -1 {
			for i := int(math.Sqrt(float64(n))); i > 0; i-- {
				if (n-s)%i == 0 && f((n-s)/i+1, n) == s {
					ans = (n-s)/i + 1
				}
			}
		}
	}
	fmt.Println(ans)
}

func max(a ...int) int {
	r := a[0]
	for i := 0; i < len(a); i++ {
		if r < a[i] {
			r = a[i]
		}
	}
	return r
}

func min(a ...int) int {
	r := a[0]
	for i := 0; i < len(a); i++ {
		if r > a[i] {
			r = a[i]
		}
	}
	return r
}

type scanner struct {
	r   *bufio.Reader
	buf []byte
	p   int
}

func newScanner() *scanner {
	rdr := bufio.NewReaderSize(os.Stdin, 10000)
	return &scanner{r: rdr}
}
func (s *scanner) next() string {
	s.pre()
	start := s.p
	for ; s.p < len(s.buf); s.p++ {
		if s.buf[s.p] == ' ' {
			break
		}
	}
	result := string(s.buf[start:s.p])
	s.p++
	return result
}
func (s *scanner) nextLine() string {
	s.pre()
	start := s.p
	s.p = len(s.buf)
	return string(s.buf[start:])
}
func (s *scanner) nextInt() int {
	v, _ := strconv.Atoi(s.next())
	return v
}
func (s *scanner) nextInt64() int64 {
	v, _ := strconv.ParseInt(s.next(), 10, 64)
	return v
}
func (s *scanner) pre() {
	if s.p >= len(s.buf) {
		s.readLine()
		s.p = 0
	}
}
func (s *scanner) readLine() {
	s.buf = make([]byte, 0)
	for {
		l, p, e := s.r.ReadLine()
		if e != nil {
			panic(e)
		}
		s.buf = append(s.buf, l...)
		if !p {
			break
		}
	}
}

Submission Info

Judge Result