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Copy pathFind the Minimum Number of Fibonacci Numbers Who Sum is K.py
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Find the Minimum Number of Fibonacci Numbers Who Sum is K.py
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# https://leetcode.com/problems/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k/
class Solution:
def generateFib(self, k):
# OBJECTIVE: Return a list of fibonacci numbers from 1 to k
# Create list
fib = [1, 1]
# Populate list
num = 1
while num < k:
# If the new number is less than or equal to k, update num and add it to list
if fib[-1] + fib[-2] <= k:
num = fib[-1] + fib[-2]
fib.append(num)
# If the new number is greater than k, exit loop
else:
break
return fib
def findK(self, fib, n, target):
# OBJECTIVE: Return index of element that equals or closest to target
# If target is 0, exit function
if target == 0:
return 0
# If target is greater than or equal to fib's last element, return it
if target >= fib[n - 1]:
return n - 1
# Create left and right pointers
leftPtr = 0
rightPtr = n - 1
# Do binary search to find target in fib
while leftPtr < rightPtr:
# Create middle pointer
midPtr = (leftPtr + rightPtr) // 2
# If middle element is greater than target, move rightPtr
if fib[midPtr] > target:
rightPtr = midPtr
# If middle element is less than or equal to target, move leftPtr
else:
leftPtr = midPtr + 1
# Return left pointer
return leftPtr - 1
def findMinFibonacciNumbers(self, k: int) -> int:
# OBJECTIVE: Return the minimum number of fibonacci numbers whose sum is equal to k
# If k equals to 1, return 1.
# NOTE: Added this to avoid O(n) space and run time
if k == 1:
return 1
# Generate a list of fibonacci numbers from 1 to k
fib = self.generateFib(k)
n = len(fib)
# If last element equals to k, return 1
if fib[-1] == k:
return 1
# Create a variable to hold minimum number of fibonacci numbers
minLen = 0
# Get minimum number of fibonacci numbers
while k > 0:
# Find k (or value closest to k) in fib
idx = self.findK(fib, n, k)
# Increment minLen
minLen += 1
# Update k by subtracting idx element from it
k -= fib[idx]
return minLen