LeetCode 1171 Remove zero sum linked list || Day 22|| C++|| Medium

Learn how to solve the "Remove Zero Sum Sublists" problem for linked lists! 🚀 In this tutorial, we'll explore a clever algorithm to remove consecutive sequences of nodes whose values sum up to 0. This problem is not just about coding skills but also about understanding how to manipulate linked list pointers efficiently. 💡

Steps to Solve:

Initialize Variables: 🛠️ Create a dummy node and set its next pointer to the head of the linked list. Also, initialize a prefix sum variable to 0 and an unordered map to store the prefix sums and their corresponding nodes.

Iterate Through the List: 🔄 Traverse the linked list while maintaining the prefix sum. For each node:

Add the node's value to the prefix sum.
Check if the prefix sum exists in the unordered map. If it does, it means there is a subsequence that sums up to 0.
Remove Zero Sum Sublists:

If such a sum is found, iterate from the node after the node corresponding to the prefix sum in the map to the current node. For each node in this range, remove its prefix sum entry from the map.
Finally, update the next pointer of the node corresponding to the prefix sum in the map to point to the node after the current node.
Update Map: 🗺️ If the current prefix sum doesn't exist in the map, add it along with the current node.

Return the Result: 🎯 After iterating through the list, return the next pointer of the dummy node, which points to the head of the modified linked list without zero sum sublists.

Check out the video for a detailed explanation and implementation of this efficient algorithm! 🔥🧐

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