N个人围成一个圈，从第1个人开始报数，没数到三，则这个人就要自杀，然后后面的人接着报数，怎么使得有M个人存活下来。

#include <iostream>
using namespace std;

#define N 41
#define M 3
int main(void)
{
	int man[N] = {0};
	int count = 1;
	int i = 0,pos = -1;
	int alive = 0;

	while(count <= N){
		do{
			pos = (pos + 1) % N;
			if (man[pos] == 0)
			{
				i++;
			}
			if (i == M)
			{
				i = 0;
				break;
			}

		}while(1);

		man[pos] = count;
		count++;
	}

	cout<<"Joseph arrangement: "<<endl;
	for (int i = 0; i < N; i++)
	{
		cout<<man[i]<<' ';
		if ((i + 1)%10 == 0)
		{
			cout<<endl;
		}
	}
	
	cout<<endl;
	cout<<"the number of people you want secure："<<endl;
	cin>>alive;

	cout<<"the L represent the living."<<endl;
	for (int i = 0; i < N; i++)
	{
		if (N - man[i] < alive)
		{
			cout<<"L";
		}
		else{
			cout<<"D";
		}
		if ((i + 1)%5 == 0)
		{
			cout<<"    ";
		}
	}
	cout<<"\nfinish";
	return 0;
}