LC-0724 Easy LeetCode

724. Find Pivot Index

Read the full problem statement on LeetCode.

Difficulty: easy Acceptance: 60% Topics: Array, Prefix Sum

Reading material

Arrays & Hashing 12 min Prefix Sums & Difference Arrays 11 min

Reference solution (spoiler · python)

# Time:  O(n)
# Space: O(1)

class Solution(object):
    def pivotIndex(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        total = sum(nums)
        left_sum = 0
        for i, num in enumerate(nums):
            if left_sum == (total-left_sum-num):
                return i
            left_sum += num
        return -1

Solution from kamyu104/LeetCode-Solutions · MIT