/**
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Definition for singly-linked list.
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struct ListNode {
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int val;
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ListNode *;
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ListNode(int x) : val(x), next(NULL) {}
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}; */ class Solution { public: bool hasCycle(ListNode *head) {
if(head == nullptr || head->next == nullptr) return 0; ListNode *slow = head; ListNode *fast = head; while(fast->next && fast->next->next) { fast= fast->next->next; slow= slow->next; if(slow == fast) { return 1; } } return 0;
} };