归并排序（分治）

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

void MerageSort(int *A, int low, int high);
void Merge(int *A, int low, int middle, int high);

int main()
{   

    int array[] = {2, 3, 6, 5, 4, 3, 3};
    int low = 0, high = 7;

    int i = 0;
    for(i = low; i < high; i++)
    {
        printf("%d ", array[i]);
    }
    printf("
");

    MerageSort(array, low, high - 1);

    
    system("pause");
    return 0;
}

void Merge(int *A, int low, int middle, int high)
{
    int i = low, j = middle + 1;
    int m = middle, n = high;
    int k = 0;
    int *A1 = (int*)malloc((high - low + 1)*sizeof(int));
    printf("low = %d, middle = %d, high = %d
", low, middle, high);

    while(i <= m && j <= n)
    {
        if(A[i] < A[j])
        {
            A1[k] = A[i];
            i++;
        }
        else
        {
            A1[k] = A[j];
            j++;
        }
        k++;
    }

    while(i <= m) //加到尾部
    {
        A1[k] = A[i];
        k++;
        i++;
    }

    while(j <= n) //加到尾部
    {
        A1[k] = A[j];
        k++;
        j++;
    }

    for(i = 0; i < high -low + 1; i++)
    {
        A[low + i] = A1[i];
        printf("%d ", A[low + i]);
    }
    printf("
");

    free(A1);
    A1 = NULL;
}


void MerageSort(int *A, int low, int high)
{   
    int middle = 0;
    if(low < high)
    {
        middle = (low + high)/2;
        MerageSort(A, low, middle);
        MerageSort(A, middle+1, high);
        Merge(A, low, middle, high);

    }    
}

运行结果：