class Solution {
public:
int Fibonacci(int n) {
//递归法(面试别用)
// if (n == 0) return 0;
// if (n <= 2) return 1;
// return Fibonacci(n - 1) + Fibonacci(n - 2);
//递推法
int a = 0, b = 1;
while (n -- )
{
int c = a + b;
a = b, b = c;
}
return a;
}
};