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33 | /**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
private:
ListNode *takeOneStep(ListNode *node) {
if (node)
return node->next;
return nullptr;
}
ListNode *takeTwoStep(ListNode *node) {
return takeOneStep(takeOneStep(node));
}
public:
ListNode *middleNode(ListNode *head) {
ListNode *slow = head;
ListNode *fast = head;
while (fast && fast->next) {
slow = takeOneStep(slow);
fast = takeTwoStep(fast);
}
return slow;
}
};
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