排序算法的数组实现 -- 合并排序（三）

static const int Sentinel_Card = 100000;//哨兵，假设元素值都比它小
void static Merger(int *a, int p, int q, int r)
{
int L_Size = q - p + 1;
int R_Size = r - q;

int *a1 = new int[L_Size + 1];
int *a2 = new int[R_Size + 1];

for (int i = 0; i < L_Size; i++)
a1[i] = a[p + i];

a1[L_Size] = Sentinel_Card;

for (int i = 0; i < R_Size; i++)
{
a2[i] = a[q + 1 + i];
}
a2[R_Size] = Sentinel_Card;

int m = 0, n = 0;
for (int i = p; i <= r; i ++)
{
if(a1[m] < a2
)
{
a[i] = a1[m];
m++;
}
else
{
a[i] = a2
;
n++;
}

}

}

void Merger_Sort(int *a, int p, int r)
{
if(p < r)
{
int q = (p + r)/2;
Merger_Sort(a, p, q);
Merger_Sort(a, q + 1, r);
Merger(a, p, q, r);
}
}