Problem:
Merge Sort

Write a program of a Merge Sort algorithm implemented by the following pseudocode. You should also report the number of comparisons in the Merge function.

Merge(A, left, mid, right)
n1 = mid - left;
n2 = right - mid;
create array L[0...n1], R[0...n2]
for i = 0 to n1-1
do L[i] = A[left + i]
for i = 0 to n2-1
do R[i] = A[mid + i]
L[n1] = SENTINEL
R[n2] = SENTINEL
i = 0;
j = 0;
for k = left to right-1
if L[i] <= R[j]
then A[k] = L[i]
i = i + 1
else A[k] = R[j]
j = j + 1

Merge-Sort(A, left, right){
if left+1 < right
then mid = (left + right)/2;
call Merge-Sort(A, left, mid)
call Merge-Sort(A, mid, right)
call Merge(A, left, mid, right)

Input

In the first line n is given. In the second line, n integers are given.

Output

In the first line, print the sequence S. Two consequtive elements should be separated by a space character.

In the second line, print the number of comparisons.

Constraints

n ≤ 500000

0 ≤ an element in S ≤ 109

Sample Input 1

10
8 5 9 2 6 3 7 1 10 4

Sample Output 1

1 2 3 4 5 6 7 8 9 10
34

Notes

Solution in Go (judge verdict: Accepted)

package main

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

// (sorted ints, compare count)
func mergeSort(xs []int) ([]int, int) {
	n := len(xs)
	if n <= 1 {
		return xs, 0
	}

	mid := n/2
	leftXs, leftCount := mergeSort(xs[:mid])
	rightXs, rightCount := mergeSort(xs[mid:])

	newXs := make([]int, n)
	leftN, rightN := len(leftXs), len(rightXs)
	ind, leftInd, rightInd := 0, 0, 0
	count := 0

	for leftInd < leftN && rightInd < rightN {
		if leftXs[leftInd] < rightXs[rightInd] {
			newXs[ind] = leftXs[leftInd]
			leftInd++
		} else {
			newXs[ind] = rightXs[rightInd]
			rightInd++
		}
		ind++
		count++
	}
	for leftInd < leftN {
		newXs[ind] = leftXs[leftInd]
		ind++
		leftInd++
		count++
	}
	for rightInd < rightN {
		newXs[ind] = rightXs[rightInd]
		ind++
		rightInd++
		count++
	}

	return newXs, leftCount + rightCount + count
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	xs := make([]int, n)
	for i := 0; i < n; i++ {
		x, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		xs[i] = x
	}

	sortedXs, count := mergeSort(xs)
	fmt.Println(formatInts(sortedXs))
	fmt.Println(count)
}

func formatInts(xs []int) string {
	n := len(xs)
	ss := make([]string, n)
	for i := 0; i < n; i++ {
		ss[i] = strconv.Itoa(xs[i])
	}
	return strings.Join(ss, " ")
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}