✉️문제
https://leetcode.com/problems/linked-list-cycle/description/
Linked List Cycle - LeetCode
Can you solve this real interview question? Linked List Cycle - Given head, the head of a linked list, determine if the linked list has a cycle in it. There is a cycle in a linked list if there is some node in the list that can be reached again by continuo
leetcode.com
📝 접근
방문한 노드에 방문했다는 표시를 한다. (이 문제에서는 val 변수에 Integer.MIN_VALUE 값을 넣을 수 있다)
🗝 문제풀이
public class DetectCycleInALinkedList {
public class ListNode {
int val;
ListNode next;
ListNode() {}
ListNode(int val) { this.val = val; }
ListNode(int val, ListNode next) { this.val = val; this.next = next; }
}
public boolean hasCycle(ListNode head) {
ListNode prev = null;
ListNode current = head;
while(current != null) {
if(current.val == Integer.MIN_VALUE) {
return true;
} else {
current.val = Integer.MIN_VALUE;
prev = current;
current = current.next;
}
}
return false;
}
}