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 C (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>

#define MAX 500001

void merge(int *,int,int,int);
void mergeSort(int *,int,int);

int count=0; 

int main(){
  int n,i;
  int S[MAX];

  scanf("%d",&n);
  for(i=0;i<n;i++){
    scanf("%d",&S[i]);
    if(S[i]<0 || S[i]>1000000000){
      exit(1);
    }
  }

  mergeSort(S,0,n);

  for(i=0;i<n-1;i++){
    printf("%d ",S[i]);
  }
  printf("%d\n",S[n-1]);
  printf("%d\n",count);

  return 0;
}

void merge(int *A,int l,int m,int r){
  int n1=m-l;
  int n2=r-m;
  int i,j,k;
  int *L,*R;

  L=(int *)malloc(sizeof(int)*(n1+1));
  R=(int *)malloc(sizeof(int)*(n2+1));

  for(i=0;i<=n1-1;i++){
    L[i]=A[l+i];
  }

  for(j=0;j<=n2-1;j++){
    R[j]=A[m+j];
  }

  L[n1]=1000000000;
  R[n2]=1000000000;

  i=0;
  j=0;

  for(k=l;k<=r-1;k++){
    if(L[i]<=R[j]){
      A[k]=L[i];
      i=i+1;
    }else{
      A[k]=R[j];
      j=j+1;
    }

    count++;
  }

  free(L);
  free(R);
}

void mergeSort(int *A,int left,int right){
  int mid;

  if(left+1<right){
    mid=(left+right)/2;
    mergeSort(A,left,mid);
    mergeSort(A,mid,right);
    merge(A,left,mid,right);
  }
}