LeetCode #724: Find Pivot Index
β’ 71 words β’ 1 min
LeetCode #724: Find Pivot Index:
Slow:
python
class Solution:
def pivotIndex(self, nums: List[int]) -> int:
for i, num in enumerate(nums):
if sum(nums[:i]) == sum(nums[i + 1:]):
return i
return -1Prefix sum:
python
from itertools import accumulate
class Solution:
def pivotIndex(self, nums: List[int]) -> int:
acc = list(accumulate(nums))
for i, num in enumerate(nums):
if (acc[i - 1] if i > 0 else 0) == (acc[-1] - acc[i]):
return i
return -1