30 lines
798 B
C#
30 lines
798 B
C#
namespace _142._Linked_List_Cycle_II;
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public class Solution
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{
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public ListNode? DetectCycle(ListNode head)
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{
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if (head == null)
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return null;
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ListNode? cur = head;
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int bit = 1 << 28;
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int curAbs = 0;
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while (cur != null && (curAbs & bit) == 0)
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{
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cur.val ^= bit;
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cur = cur.next;
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if (cur != null)
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curAbs = cur.val < 0 ? (cur.val * -1) : cur.val;
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}
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cur = head;
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curAbs = cur.val < 0 ? (cur.val * -1) : cur.val;
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while (cur != null && (curAbs & bit) != 0)
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{
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cur.val ^= bit;
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cur = cur.next;
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if (cur != null)
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curAbs = cur.val < 0 ? (cur.val * -1) : cur.val;
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}
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return cur;
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}
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} |