30 lines
850 B
C++
30 lines
850 B
C++
// https://leetcode.com/problems/linked-list-cycle/
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/**
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* Definition for singly-linked list.
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*/
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#include <cstddef>
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struct ListNode {
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int val;
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ListNode *next;
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ListNode(int x) : val(x), next(NULL) {}
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};
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// Pursuing the cheeky logic from last time, indeed, we can run the loop 10001 times,
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// and if the pointer still isn't at the end, we know it must be stuck in a loop
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// (since the longest possible list is only 10000).
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// This actually performs surprisingly well on the leaderboard, despite being totally, totally
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// overkill for almost all the cases :)
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class Solution {
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public:
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bool hasCycle(ListNode *head) {
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ListNode* ptr = head;
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for (int i = 0; i < 10001; i++) {
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if (ptr == nullptr) {
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return false;
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}
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ptr = ptr->next;
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}
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return true;
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}
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};
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