题目：

 

 

 

解答：

 

 

 

 1 class Solution {
 2     int f(int n, int m) 
 3     {
 4         if (n == 1)
 5         {
 6             return 0;
 7         }
 8         int x = f(n - 1, m);
 9         return (m + x) % n;
10     }
11 public:
12     int lastRemaining(int n, int m) 
13     {
14         return f(n, m);
15     }
16 
17 };

 

方法二：数学+迭代

class Solution {
public:
    int lastRemaining(int n, int m) {
        int f = 0;
        for (int i = 2; i != n + 1; ++i)
            f = (m + f) % i;
        return f;
    }
};