# Program to find minimum number of Fibonacci numbers to add up to n in Python?

Suppose we have a number n; we have to find the minimum number of Fibonacci numbers required to add up to n.

So, if the input is like n = 20, then the output will be 3, as We can use the Fibonacci numbers [2, 5, 13] to sum to 20.

To solve this, we will follow these steps

• res := 0

• fibo := a list with values [1, 1]

• while last element of fibo <= n, do

• x := sum of last two elements of fibo

• insert x into fibo

• while n is non-zero, do

• while last element of fibo > n, do

• delete last element from fibo

• n := n - last element of fibo

• res := res + 1

• return res

Let us see the following implementation to get better understanding

## Example

class Solution:
def solve(self, n):
res = 0
fibo = [1, 1]
while fibo[-1] <= n:
fibo.append(fibo[-1] + fibo[-2])

while n:
while fibo[-1] > n:
fibo.pop()
n -= fibo[-1]
res += 1
return res

ob = Solution()
n = 20
print(ob.solve(n))

20

## Output

3

Updated on: 10-Nov-2020

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