归并排序模板:
void merge_sort(int q[], int l, int r)
{
if(l >= r) return;
int mid = l + r >> 1;
merge_sort(q, l, mid), merge_sort(q, mid + 1, r);
int i = l, j = mid + 1, k = 0;
while(i <= mid && j <= r)
{
if(q[i] < q[j]) temp[k++] = q[i++];
else temp[k++] = q[j++];
}
while(i <= mid) temp[k++] = q[i++];
while(j <= r) temp[k++] = q[j++];
for(k = 0, i = l; i <= r; i++, k++) q[i] = temp[k];
}