Sortmethod/归并排序

//归并排序
void copyArray(int source[], int dest[],int len,int first)  
{  
    int i;  
    int j=first;  
    for(i=0;i<len;i++)  
    {  
        dest[j] = source[i];  
        j++;  
    }  
          
} 
//相邻两个有序子序列的归并函数，将a[low...mid]和a[mid+1...high]归并到T[LOW..high]中 
void merge(int a[],int left,int right)  
{  
    int begin1 = left;  
    int mid = (left+right)/2 ;  
    int begin2 = mid+1;  
    int k=0;  
    int newArrayLen = right-left+1;  
    int *b = (int*)malloc(newArrayLen*sizeof(int));  
    while(begin1<=mid && begin2<=right)  
    {  
        if(a[begin1]<=a[begin2])  
            b[k++] = a[begin1++];  
        else  
            b[k++] = a[begin2++];  
    }  
    while(begin1<=mid)  
        b[k++] = a[begin1++];  
    while(begin2<=right)  
        b[k++] = a[begin2++];  
    copyArray(b,a,newArrayLen,left);  
    free(b);  
}  
//归并函数,将a[low...high]归并到T[low...high]中
void mergeSort(int a[],int left,int right)  
{  
    int i;  
    // 保证至少有两个元素  
    if(left < right)  
    {  
        i = (left+right)/2;  
        mergeSort(a,left,i);  
        mergeSort(a,i+1,right);  
        merge(a,left,right);  
    }  
} 
void MergeSort(int a[],int n)
{
	mergeSort(a,0,n-1);
}
int main()
{
	int n;
	cin>>n;
	int *a=new int[n];
	
	for(int j=0;j<n;j++)
		cin>>a[j];
	MergeSort(a,n);
	for(int i=0;i<n;i++)
		cout<<a[i];
	delete []a;
	
}