Problem:
Score : 500 points

Problem Statement

We have N logs of lengths A_1,A_2,\cdots A_N.

We can cut these logs at most K times in total. When a log of length L is cut at a point whose distance from an end of the log is t (0<t<L), it becomes two logs of lengths t and L-t.

Find the shortest possible length of the longest log after at most K cuts, and print it after rounding up to an integer.

Constraints

1 \leq N \leq 2 \times 10^5

0 \leq K \leq 10^9

1 \leq A_i \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N K
A_1 A_2 \cdots A_N

Output

Print an integer representing the answer.

Sample Input 1

2 3
7 9

Sample Output 1

4

First, we will cut the log of length 7 at a point whose distance from an end of the log is 3.5, resulting in two logs of length 3.5 each.

Next, we will cut the log of length 9 at a point whose distance from an end of the log is 3, resulting in two logs of length 3 and 6.

Lastly, we will cut the log of length 6 at a point whose distance from an end of the log is 3.3, resulting in two logs of length 3.3 and 2.7.

In this case, the longest length of a log will be 3.5, which is the shortest possible result. After rounding up to an integer, the output should be 4.

Sample Input 2

3 0
3 4 5

Sample Output 2

5

Sample Input 3

10 10
158260522 877914575 602436426 24979445 861648772 623690081 433933447 476190629 262703497 211047202

Sample Output 3

292638192

Solution in Go (1.14.1) (judge verdict: Wrong Answer)

package main

import (
	"bufio"
	"fmt"
	"io"
	"math"
	"os"
	"sort"
	"strconv"
	"strings"
)

func main() {
	io := NewIo(os.Stdin, os.Stdout)
	defer io.Flush()
	n, k := io.NextInt(), io.NextInt()
	a := io.NextInts(n)
	ans := solve(n, k, a)
	io.Println(ans)
}

func solve(n, k int, a []int) int {
	if k == 0 {
		return Max(a...)
	}
	divConut := func(x float64) int {
		cnt := 0
		for i := range a {
			if float64(a[i]) <= x {
				continue
			}
			cnt += int(math.Ceil(float64(a[i])/x)) - 1
		}
		return cnt
	}
	x := sort.Search(maxIter, func(x int) bool { return divConut(float64(x)/10) <= k })
	if x == maxIter {
		panic("error")
	}
	return int(math.Ceil(float64(x) / 10))
}

const maxIter = 1e12

// Max returns max value of inputs
func Max(a ...int) (max int) {
	for i, ai := range a {
		if i == 0 || ai > max {
			max = ai
		}
	}
	return max
}

// Io is I/O object
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

// NewIo returns a new Io instance
func NewIo(r io.Reader, w io.Writer) *Io {
	return &Io{
		reader: bufio.NewReader(r),
		writer: bufio.NewWriter(w),
	}
}

// Flush flushes writer
func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

// NextLine scans a line from stdin
func (io *Io) NextLine() string {
	var buffer []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buffer = append(buffer, line...)
		if !isPrefix {
			break
		}
	}
	return string(buffer)
}

// Next return a word from stdin
func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	r := io.tokens[io.nextToken]
	io.nextToken++
	return r
}

// NextInt returns an integer from stdin
func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

// NextInts returns n integers from stdin
func (io *Io) NextInts(n int) []int {
	ret := make([]int, n)
	for i := 0; i < n; i++ {
		ret[i] = io.NextInt()
	}
	return ret
}

// Println is a wrapper of fmt.Fprintln
func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}