Code RoomFind balance index
MediumPrep Room Coding #383

Find balance index

CodingDatabases & SQLAlgorithms & data structuresEntry–Mid~15 min

Given a list of integers, find the leftmost balance index: a position where the sum of all entries strictly to its left equals the sum of all entries strictly to its right (the entry at the position itself joins neither side). Sums over no entries count as 0. Return that index, or -1 if no position balances. Example: [1, 7, 3, 6, 5, 6] returns 3, since 1+7+3 = 5+6.

Implement
balance_index(nums: list[int]) → int
Examples
in[[1,7,3,6,5,6]]out3
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 15 min
InputExpectedGot
[[1,7,3,6,5,6]]3not run yetsample