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Commit c25c3d6

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LinkedList Cycle Detection
1 parent c30407b commit c25c3d6

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2 files changed

+62
-2
lines changed

2 files changed

+62
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lines changed

‎src/main/kotlin/Main.kt

Lines changed: 14 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,7 @@
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package main.kotlin
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import main.kotlin.dsalgoleetcode.LinkedListCycleDetection
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import main.kotlin.dsalgoleetcode.ListNode
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import main.kotlin.dsalgoleetcode.LongestSubstring
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import main.kotlin.dsalgoleetcode.TwoSum
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@@ -11,11 +13,21 @@ fun main() {
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// Calling Two Sum class
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val twoSum = TwoSum()
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val result = twoSum.twoSum(nums = intArrayOf(1, 2, 3, 4, 5), target = 9)
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println("Indices: ${result.joinToString(",")}")
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// Calling Longest Substring
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val longestSubstring = LongestSubstring()
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val lsResult = longestSubstring.lengthOfLongestSubstring(s = "abcabcbbb")
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println("Indices: ${result.joinToString(",")}")
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println("Longest Substring : $lsResult")
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// Calling LinkedList Cycle Detection
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val linkedListCycleDetection = LinkedListCycleDetection()
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val node1 = ListNode(1)
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val node2 = ListNode(2)
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val node3 = ListNode(3)
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node1.next = node2
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node2.next = node3
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node3.next = node1 // cycle back to x
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val llcdResult = linkedListCycleDetection.hasCycle(node1)
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println("Has cycle $llcdResult")
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}
Lines changed: 48 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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package main.kotlin.dsalgoleetcode
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/**
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* Linked List Cycle
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*
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* Given head, the head of a linked list, determine if the linked list has a cycle in it.
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* There is a cycle in a linked list if there is some node in the list that can be reached
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* again by continuously following the next pointer. Internally, pos is used to denote the
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* index of the node that tail's next pointer is connected to. Note that pos is not passed
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* as a parameter.
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*
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* Return true if there is a cycle in the linked list. Otherwise, return false.
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*
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* Input: head = [3,2,0,-4], pos = 1
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* Output: true
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* Explanation: There is a cycle in the linked list, where the tail connects to
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* the 1st node (0-indexed).
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* */
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class LinkedListCycleDetection {
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/**
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* Example:
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* var li = ListNode(5)
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* var v = li.`val`
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* Definition for singly-linked list.
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* class ListNode(var `val`: Int) {
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* var next: ListNode? = null
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* }
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*/
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fun hasCycle(head: ListNode?): Boolean {
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var slow = head
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var fast = head
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while (fast != null && fast.next != null) {
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slow = slow?.next
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fast = fast.next?.next
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if (slow == fast)
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return true
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}
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return false
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}
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}
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class ListNode(var `val`: Int) {
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var next: ListNode? = null
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}

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