1 class Solution: 2 def fib(self, n: int) -> int: 3 if n <= 2: 4 return n 5 6 prev1, prev2 = 0, 1 7 for _ in range(2, n+1): 8 sum_value = prev1 + prev2 9 prev1, prev2 = prev2, sum_value 10 11 return prev2
1 class Solution: 2 def climbStairs(self, n: int) -> int: 3 if n <= 1: 4 return n 5 6 prev1, prev2 = 1, 2 7 8 for _ in range(3, n + 1): 9 curr = prev1 + prev2 10 prev1, prev2 = prev2, curr 11 12 return prev2