13 lines
329 B
Python
13 lines
329 B
Python
def detectCycle(self, head):
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slow, fast = head, head
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while fast and fast.next:
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slow = slow.next
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fast = fast.next.next
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if slow == fast: break
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if not fast or not fast.next: return None
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slow = head
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while slow != fast:
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slow = slow.next
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fast = fast.next
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return slow |