[Swift]LeetCode147. 对链表进行插入排序 | Insertion Sort List
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➤微信公众号：山青咏芝（shanqingyongzhi）
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Sort a linked list using insertion sort.
A graphical example of insertion sort. The partial sorted list (black) initially contains only the first element in the list.
With each iteration one element (red) is removed from the input data and inserted in-place into the sorted list
Algorithm of Insertion Sort:
- Insertion sort iterates, consuming one input element each repetition, and growing a sorted output list.
- At each iteration, insertion sort removes one element from the input data, finds the location it belongs within the sorted list, and inserts it there.
- It repeats until no input elements remain.
Example 1:
Input: 4->2->1->3 Output: 1->2->3->4
Example 2:
Input: -1->5->3->4->0 Output: -1->0->3->4->5
对链表进行插入排序。
插入排序的动画演示如上。从第一个元素开始，该链表可以被认为已经部分排序（用黑色表示）。
每次迭代时，从输入数据中移除一个元素（用红色表示），并原地将其插入到已排好序的链表中。
插入排序算法：
- 插入排序是迭代的，每次只移动一个元素，直到所有元素可以形成一个有序的输出列表。
- 每次迭代中，插入排序只从输入数据中移除一个待排序的元素，找到它在序列中适当的位置，并将其插入。
- 重复直到所有输入数据插入完为止。
示例 1：
输入: 4->2->1->3 输出: 1->2->3->4
示例 2：
输入: -1->5->3->4->0 输出: -1->0->3->4->5
1436ms
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * public var val: Int 5 * public var next: ListNode? 6 * public init(_ val: Int) { 7 * self.val = val 8 * self.next = nil 9 * } 10 * } 11 */ 12 class Solution { 13 func insertionSortList(_ head: ListNode?) -> ListNode? { 14 let dummyHead = ListNode(-1) 15 var sortedNodeIdx: ListNode? = dummyHead 16 var curr = head 17 18 while let _ = curr { 19 while let sortedNodeIdxNext = sortedNodeIdx?.next, 20 sortedNodeIdxNext.val < curr!.val { 21 sortedNodeIdx = sortedNodeIdxNext 22 } 23 24 let currNext = curr?.next 25 let sortedNodeIdxNext = sortedNodeIdx?.next 26 sortedNodeIdx?.next = curr 27 curr?.next = sortedNodeIdxNext 28 sortedNodeIdx = dummyHead 29 curr = currNext 30 } 31 32 return dummyHead.next 33 } 34 }
2672ms
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * public var val: Int 5 * public var next: ListNode? 6 * public init(_ val: Int) { 7 * self.val = val 8 * self.next = nil 9 * } 10 * } 11 */ 12 class Solution { 13 func insertionSortList(_ head: ListNode?) -> ListNode? { 14 let dummyHead = ListNode(0) 15 dummyHead.next = head 16 var last = dummyHead 17 var p = head 18 while p != nil { 19 var tail = p?.next 20 var q = dummyHead 21 while q !== last { 22 if p!.val < q.next!.val { 23 p!.next = q.next 24 q.next = p 25 last.next = tail 26 break 27 } 28 q = q.next! 29 } 30 if q === last { 31 last = p! 32 } 33 p = tail 34 } 35 return dummyHead.next 36 } 37 }
2916ms
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * public var val: Int 5 * public var next: ListNode? 6 * public init(_ val: Int) { 7 * self.val = val 8 * self.next = nil 9 * } 10 * } 11 */ 12 class Solution { 13 14 func insertionSortList(_ head: ListNode?) -> ListNode? { 15 var result: ListNode? = nil 16 var cur: ListNode? = head 17 while let curSafe = cur { 18 let newNode = ListNode(curSafe.val) 19 guard let resultSafe = result else { 20 result = newNode 21 cur = curSafe.next 22 continue 23 } 24 if resultSafe.val > curSafe.val { 25 let resultOld = resultSafe 26 result = newNode 27 newNode.next = resultOld 28 cur = curSafe.next 29 continue 30 } 31 var insertPos: ListNode? = result 32 while insertPos?.next != nil && insertPos!.next!.val < curSafe.val { 33 insertPos = insertPos?.next 34 } 35 newNode.next = insertPos?.next 36 insertPos?.next = newNode 37 cur = cur?.next 38 } 39 return result 40 } 41 }
3660ms
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * public var val: Int 5 * public var next: ListNode? 6 * public init(_ val: Int) { 7 * self.val = val 8 * self.next = nil 9 * } 10 * } 11 */ 12 class Solution { 13 func insertionSortList(_ head: ListNode?) -> ListNode? { 14 if head == nil || head?.next == nil { return head } 15 let dummyNode = ListNode(-1) 16 dummyNode.next = head 17 var sortedIdx: ListNode? = dummyNode 18 var currNode = head?.next 19 head?.next = nil 20 21 while currNode != nil { 22 while sortedIdx?.next != nil { 23 if currNode!.val < sortedIdx!.next!.val { 24 let sortedNext = sortedIdx?.next 25 let currNext = currNode?.next 26 sortedIdx?.next = currNode 27 currNode?.next = sortedNext 28 currNode = currNext 29 sortedIdx = dummyNode 30 break 31 } else { 32 sortedIdx = sortedIdx?.next 33 if sortedIdx?.next == nil { 34 // currNode is the biggest one in the sortedLinkedList 35 let currNext = currNode?.next 36 sortedIdx?.next = currNode 37 currNode?.next = nil 38 currNode = currNext 39 sortedIdx = dummyNode 40 break 41 } 42 } 43 } 44 } 45 46 return dummyNode.next 47 } 48 }
3994ms
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * public var val: Int 5 * public var next: ListNode? 6 * public init(_ val: Int) { 7 * self.val = val 8 * self.next = nil 9 * } 10 * } 11 */ 12 class Solution { 13 14 // key = node position 15 // value = node object 16 // var hash: [Int: ListNode] = [:] 17 // var list: ListNode? 18 19 var array: [ListNode] = [] 20 21 func insertionSortList(_ head: ListNode?) -> ListNode? { 22 guard head != nil, 23 head!.next != nil else { 24 return head 25 } 26 27 // build array 28 var node = head 29 while node != nil { 30 array.append(node!) 31 node = node!.next 32 } 33 // print("array.count = \(array.count)") 34 35 // var i = 1 36 for i in 1..<array.count { 37 // print("i = \(i)") 38 39 var j = i 40 while j > 0 { 41 // print("j = \(j)") 42 if array[j].val < array[j-1].val { 43 // array[j-1].next = array[j].next 44 // array[j].next = array[j-1] 45 array.swapAt(j, j-1) 46 j -= 1 47 } else { 48 break 49 } 50 } 51 } 52 53 // connect nodes 54 for i in 0..<array.count-1 { 55 array[i].next = array[i+1] 56 } 57 array[array.count-1].next = nil 58 59 return array[0] 60 } 61 }
