代码

void swap(unsigned &a, unsigned &b)
{
	unsigned t = b;
	b = a, a = t;
}

void merge(unsigned *a, int l, int r)
{
	int mid = a[l + r >> 1], i = l, j = r;
	do
	{
		while(a[i] < mid)
			i ++;
		while(a[j] > mid)
			j --;
		if(i <= j)
			swap(a[i], a[j]), i ++, j --;
	}while(i <= j);
	if(l < j)
		merge(a, l, j);
	if(i < r)
		merge(a, i, r);
}

void sort(unsigned *a, int n)
{
	merge(a, 0, n - 1);
}

评测结果