g0101_0200.s0141_linked_list_cycle.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g0101_0200.s0141_linked_list_cycle;
// #Easy #Top_100_Liked_Questions #Top_Interview_Questions #Hash_Table #Two_Pointers #Linked_List
// #Data_Structure_I_Day_7_Linked_List #2022_02_23_Time_0_ms_(100.00%)_Space_46.5_MB_(9.38%)
import com_github_leetcode.ListNode;
/*
* Definition for singly-linked list.
* class ListNode {
* int val;
* ListNode next;
* ListNode(int x) {
* val = x;
* next = null;
* }
* }
*/
public class Solution {
public boolean hasCycle(ListNode head) {
if (head == null) {
return false;
}
ListNode fast = head.next;
ListNode slow = head;
while (fast != null && fast.next != null) {
if (fast == slow) {
return true;
}
fast = fast.next.next;
slow = slow.next;
}
return false;
}
}