Fibonacci

解法一：递归

long long Fibonacci(unsigned int n){    int result[3] = {0,1,2};    if (n <= 2)        return result[n];    return Fibonacci(n - 1) + Fibonacci(n - 2);}

解法二：非递归

long long Fibonacci(unsigned int n){    long long first, second, result;    first = second = result = 1;    if (n < 2)        return result;    else    {        while(n >= 2)        {            first = second;            second = result;            result = first + second;            n--;        }    return result;    }}