二路归并排序

/**
    二路归并排序

*/

#include<cstdio>

//待排序测试的数组
int arry[] = {7,11,9,15,18,22,0,1,102,18,19};

void mergeSort(int arr[],int s,int t);
void myMerge(int arr[],int s,int m,int t);
void printArr(int arr[],int s, int t);

int main()
{
    printf("Before merge-sorting the array is :\n");
    printArr(arry,0,10);

    mergeSort(arry,0,10);

    printf("After merge-sorting the array is :\n");
    printArr(arry,0,10);

    return 0;
}

//归并排序
void mergeSort(int arr[],int s,int t)
{
    if(s<t)
    {
        int m = (s+t)/2;
        mergeSort(arr,s,m);
        mergeSort(arr,m+1,t);
        myMerge(arr,s,m,t);
    }
    else
    {
        return ;
    }
}

//合并两个排好序的数组
void myMerge(int arr[],int s,int m,int t)
{
    int i = s;
    int j = m+1;
    int p = 0;
    //这里借用了一个中间数组来合并
    int newArr[t-s+1];

    while(i<=m&&j<=t){
        if(arr[i]<arr[j]){
            newArr[p++] = arr[i++];
        }else{
            newArr[p++] = arr[j++];
        }
    }

    while(i<=m)
        newArr[p++] = arr[i++];
    while(j<=t)
        newArr[p++] = arr[j++];

    p = 0;
    for(int k=s;k<=t;k++)
        arr[k] = newArr[p++];
}
//打印数组
void printArr(int arr[],int s, int t)
{
    for(int i=s;i<=t;i++)
        printf("%d ",arr[i]);
    printf("\n");
}