不知道这个归并排序错在哪了，没有用动态内存分配。


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


void merge(int* arr,int left,int right,int mid){
    int Arr[20];
    int M=right-left;
    int k=0;
    int t=mid+1;
    while(left<=mid&&t<=right){
        if(arr[left]<arr[t]){
            Arr[k++]=arr[left++];
        }else{
            Arr[k++]=arr[t++];
        }
    }
    while(left<=mid)
        Arr[k++]=arr[left++];
    while(t<=right)
        Arr[k++]=arr[t++];
    
    int i;
    for(i=0;i<=M;i++){
        arr[i]=Arr[i];
    }
}

void merge_sort(int* arr,int left,int right){
    if(right==left)
        return ;
        
    int mid=(right+left)/2;
    merge_sort(arr,left,mid);
    merge_sort(arr,mid+1,right);
    
    merge(arr,left,right,mid);
}

void print(int* arr,int n){
    int i;
    for(i=0;i<n;i++)
        printf("%d",arr[i]);
}

int main(){
    int arr[5]={5,4,3,2,1};
    merge_sort(arr,0,4);
    print(arr,5);
    
    return 0; 
}