Largest Subarray with 0 Sum

The problem. Given an array arr of integers (positive, negative or zero), return the length of the longest subarray — a run of consecutive elements — whose sum is 0. If there is none, return 0.

Example

arr = [15, -2, 2, -8, 1, 7, 10, 23]  ->  5    ([-2, 2, -8, 1, 7])
arr = [1, 2, -3, 3, -1, -2]          ->  6    (the whole array)
arr = [1, 2, 3]                      ->  0    (no subarray adds up to 0)