圆圈中最后剩下的数字

题目：0, 1, …, n-1这n个数字排成一个圆圈，从数字0开始每次从这个圆圈里删除第m个数字。求出这个圆圈里剩下的最后一个数字。

方法：用环形链表模拟圆圈

int lastRemaining(int n, int m)
{
	if (n < 1 || m < 1)
		return -1;

	unsigned int i = 0;
	list<int> numbers;
	for (i = 0;i < n;++i)
		numbers.push_back(i);

	list<int>::iterator current = numbers.begin();
	while (numbers.size() > 1)
	{
		for (i = 1;i < m;++i)
		{
			++current;
			if (current == numbers.end())
				current = numbers.begin();
		}
		list<int>::iterator next = ++current;
		if (next == numbers.end())
			next = numbers.begin();

		--current;
		numbers.erase(current);
		current = next;
	}
	return *(current);
}