To find subarrays with 0 sum, find prefix sum values of all elements. Then while traversing, if the prefix sum value of any element equals that of another element later, the subarray in between is a 0-sum subarray. More formally:
For indices a and b where a < b:
If prefix[b] == prefix[a], sum(a, b, array) = 0 .
{% embed url="https://leetcode.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list/description/" %}
{% embed url="https://leetcode.com/problems/contiguous-array/description" %}