solutions/0509-Fibonacci-Number/0509.py

class Solution:
    def fib(self, n: int) -> int:
        # solution one: 递归
        if n == 0:
            return 0
        if n == 1:
            return 1
        return self.fib(n - 1) + self.fib(n - 2)
        
        # solution two: 动态规划
        dp_0, dp_1 = 0, 1
        for _ in range(n):
            dp_0, dp_1 = dp_1, dp_0 + dp_1
        return dp_0