Commit fb52881

committed

updates linked list cycle

1 parent c451a76 commit fb52881Copy full SHA for fb52881

File tree

+12

-13

lines changed

+12

-13

lines changed

Lines changed: 12 additions & 13 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,26 +1,25 @@`
`1`		`-importjava.util.HashSet;`
`2`		`-importjava.util.Set;`
	`1`	`+// T: O(n)`
	`2`	`+// S: O(1)`
`3`	`3`
`4`	`4`	`public class LinkedListCycle {`
`5`		`- static class ListNode {`
	`5`	`+ privatestatic class ListNode {`
`6`	`6`	`int val;`
`7`	`7`	`ListNode next;`
`8`	`8`	`ListNode(int x) {`
`9`		`- val = x;`
`10`		`- next = null;`
	`9`	`+ val = x;`
	`10`	`+ next = null;`
`11`	`11`	`}`
`12`	`12`	`}`
`13`	`13`
`14`	`14`	`public boolean hasCycle(ListNode head) {`
`15`		`- Set<ListNode> nodes = new HashSet<>();`
`16`		`- while (head != null) {`
`17`		`- if (nodes.contains(head)) {`
`18`		`- return true;`
`19`		`- } else {`
`20`		`- nodes.add(head);`
`21`		`- }`
`22`		`- head = head.next;`
	`15`	`+ if (head == null) return false;`
	`16`	`+`
	`17`	`+ for (ListNode slow = head, fast = head.next; fast != null && fast.next != null ; ) {`
	`18`	`+ if (slow == fast) return true;`
	`19`	`+ slow = slow.next;`
	`20`	`+ fast = fast.next.next;`
`23`	`21`	`}`
	`22`	`+`
`24`	`23`	`return false;`
`25`	`24`	`}`
`26`	`25`	`}`

Comments

(0)