孩子们的游戏(圆圈中最后剩下的数)

class Solution {
public:
int LastRemaining_Solution(unsigned int n, unsigned int m)
{
if(n < 0 || m < 1)
return -1;
int last = 0;
for(int i = 2; i <= n; i ++){
last = (last + m) % i;
}
return last;
}
};