僞代碼
MERGE(A,p,q,r)
n1=q-p+1;
n2=r-q;
create new arrays L[n1+1] and R[n2+1]
for i=0 to n1-1
L[i]=A[p+i]
for j=0 to n2-1
R[j]=A[q+1+j]
L[n1]=1000//假設1000是無窮大
R[n2]=1000
i=j=0
for k=p to r
if(L[i]<=R[j])
A[k]=L[i]
i=i+1
else
A[k]=R[j]
j=j+1
MERGE_SORT(A,p,r)
if p<r
q=floor((p+r)/2)
MERGE_SORT(A,p,q)
MERGE_SORT(A,q+1,r)
MERGE(A,p,q,r)
c實作
void main(){
int A[]={,,,,,,,};
int i;
int len=sizeof(A)/sizeof(A[]);
merge_sort(A,,);
for(i=;i<len;i++){
printf("%d ",A[i]);
}
}
void merge(int A[],int p,int q,int r){
int n1,n2,i,j,k;
n1=q-p+;
n2=r-q;
int L[n1+];
int R[n2+];
for(i=;i<n1;i++){
L[i]=A[p+i];
}
for(j=;j<n2;j++){
R[j]=A[q+j+];
}
L[n1]=;//假設100是無窮大的數
R[n2]=;
i=;
j=;
for(k=p;k<=r;k++){
if(L[i]<=R[j]){
A[k]=L[i];
i=i+;
}else{
A[k]=R[j];
j=j+;
}
}
}
void merge_sort(int A[],int p,int r){
int q;
if(p<r){
q=floor((p+r)/);
merge_sort(A,p,q);
merge_sort(A,q+,r);
merge(A,p,q,r);
}
}
java實作
public class Main {
public static void main(String[] args) {
int [] arr={,,,,,,,};
merge_sort(arr,,);
for(int i=;i<arr.length;i++)
System.out.print(arr[i]+" ");
}
public static void merge(int [] arr,int p,int q,int r){
int len1=q-p+;
int len2=r-q;
int [] arrLeft=new int[len1+];
int [] arrRight=new int[len2+];
for(int i=;i<len1;i++){
arrLeft[i]=arr[p+i];
}
for(int j=;j<len2;j++){
arrRight[j]=arr[q++j];
}
arrLeft[len1]=;
arrRight[len2]=;
int i=;
int j=;
for(int k=p;k<=r;k++){
if(arrLeft[i]<=arrRight[j]){
arr[k]=arrLeft[i];
i++;
}else{
arr[k]=arrRight[j];
j++;
}
}
}
public static void merge_sort(int [] arr,int p,int r){
if(p<r){
int q=(int)Math.floor((p+r)/);
merge_sort(arr,p,q);
merge_sort(arr,q+,r);
merge(arr,p,q,r);
}
}
}