递归与二叉树_leetcode98

class Solution(object):


    def zhuhanshu(self,n):
        self.count = 0
 self.memo = [-1 for i in range(n+1)]


 def fib1(self,n):
 if n == 0 or n == 1:
 return 1
 else:
 return self.fib(n-1)+self.fib(n-2)



 # 记忆化搜索
 def fib2(self,n):

 self.count += 1

 if n == 1 or n == 0:
 return 1


 if self.memo[n] == -1:
 self.memo[n] = self.fib2(n-1)+self.fib2(n-2)
 return self.memo[n]


 def fib2(self,n):
 memo = [-1 for i in range(n+1)]

 memo[0] = 1
 memo[1] = 1

 for i in range(2,n+1):
 memo[i] = memo[i-1] + memo[i-2]
 return memo[n]