剑指offer-斐波那契数列

 1 class Solution {
 2 public:
 3     int Fibonacci(int n) {
 4         int a,b;
 5         a = 1;
 6         b = 1;
 7         if(n == 0)
 8         {
 9             return 0;
10         }
11         else if(n == 1)
12         {
13             return 1;
14         }
15         else if(n == 2)
16         {
17             return 1;
18         }
19         else
20         {
21             int c;
22             for(int i = 3;i <= n;++i)
23             {
24                 c = a + b;
25                 a = b;
26                 b = c;
27             }
28             return c;
29         }
30     }
31 };