约瑟夫环

1. 循环

#include <iostream>
using namespace std;

int joseph(const int n, const int m)
{
	int* arr = new int[n];
	for (int i = 0; i < n; ++i) arr[i] = 1;
	int i = 0;
	int j = 0;
	int count = n;
	while (count > 1)
	{
		if (arr[i] == 1)
		{
			if (++j == m)
			{
				arr[i] = 0;
				--count;
				j = 0;
			}
		}
		if (++i == n) i = 0;
	}
	int res = 0;
	for (int i = 0; i < n; ++i)
	{
		if (arr[i] == 1)
		{
			res = i;
			break;
		}
	}
	delete[] arr;
	return res;
}

2. 递归

#include <iostream>
using namespace std;

int joseph(const int n, const int m)
{
	if (n < 1 || m < 1) return -1;
	if (n == 1) return 0;
	return (joseph(n - 1, m) + m) % n;
}