圆圈中剩下的最大数字

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