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| 1 | +/* |
| 2 | +Author : Saransh Bangar |
| 3 | +Date : 12/03/2024 |
| 4 | +Problem : Remove Zero Sum Consecutive Nodes from Linked List |
| 5 | +Difficulty : Medium |
| 6 | +Problem Link : https://leetcode.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list/description/ |
| 7 | +Video Solution : NA |
| 8 | +*/ |
| 9 | + |
| 10 | + |
| 11 | +/** |
| 12 | + * Definition for singly-linked list. |
| 13 | + * struct ListNode { |
| 14 | + * int val; |
| 15 | + * ListNode *next; |
| 16 | + * ListNode() : val(0), next(nullptr) {} |
| 17 | + * ListNode(int x) : val(x), next(nullptr) {} |
| 18 | + * ListNode(int x, ListNode *next) : val(x), next(next) {} |
| 19 | + * }; |
| 20 | + */ |
| 21 | +class Solution { |
| 22 | +public: |
| 23 | + ListNode* removeZeroSumSublists(ListNode* head) |
| 24 | + { |
| 25 | + ListNode* front = new ListNode(0, head); |
| 26 | + ListNode* current = front; |
| 27 | + int prefixSum = 0; |
| 28 | + unordered_map<int, ListNode*> prefixSumToNode; |
| 29 | + prefixSumToNode[0] = front; |
| 30 | + |
| 31 | + while (current != nullptr) |
| 32 | + { |
| 33 | + prefixSum += current->val; |
| 34 | + prefixSumToNode[prefixSum] = current; |
| 35 | + current = current->next; |
| 36 | + } |
| 37 | + |
| 38 | + prefixSum = 0; |
| 39 | + current = front; |
| 40 | + |
| 41 | + while (current != nullptr) |
| 42 | + { |
| 43 | + prefixSum += current->val; |
| 44 | + current->next = prefixSumToNode[prefixSum]->next; |
| 45 | + current = current->next; |
| 46 | + } |
| 47 | + return front->next; |
| 48 | + } |
| 49 | +}; |
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