From cb0f5906fdf7a22a097958cbb89783905baf970f Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Sat, 8 Jan 2022 23:55:34 +0800 Subject: [PATCH 01/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=88=E9=93=BE?= =?UTF-8?q?=E8=A1=A8=E7=90=86=E8=AE=BA=E5=9F=BA=E7=A1=80.md=EF=BC=89?= =?UTF-8?q?=EF=BC=9A=E5=A2=9E=E5=8A=A0JS=E5=92=8CTS=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/链表理论基础.md | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/problems/链表理论基础.md b/problems/链表理论基础.md index 02b7029e..109aa1ed 100644 --- a/problems/链表理论基础.md +++ b/problems/链表理论基础.md @@ -168,6 +168,32 @@ public class ListNode { } ``` +JavaScript: + +```javascript +class ListNode { + val; + next = null; + constructor(value) { + this.val = value; + this.next = null; + } +} +``` + +TypeScript: + +```typescript +class ListNode { + public val: number; + public next: ListNode = null; + constructor(value: number) { + this.val = value; + this.next = null; + } +} +``` + Python： From 1c595ed05192de37b7c9927b826a365c96ed2fae Mon Sep 17 00:00:00 2001 From: Du Date: Sun, 9 Jan 2022 08:52:20 +0800 Subject: [PATCH 02/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0105.=20=E4=BB=8E?= =?UTF-8?q?=E5=89=8D=E5=BA=8F=E4=B8=8E=E4=B8=AD=E5=BA=8F=E9=81=8D=E5=8E=86?= =?UTF-8?q?=E5=BA=8F=E5=88=97=E6=9E=84=E9=80=A0=E4=BA=8C=E5=8F=89=E6=A0=91?= =?UTF-8?q?=E3=80=81106.=20=E4=BB=8E=E4=B8=AD=E5=BA=8F=E4=B8=8E=E5=90=8E?= =?UTF-8?q?=E5=BA=8F=E9=81=8D=E5=8E=86=E5=BA=8F=E5=88=97=E6=9E=84=E9=80=A0?= =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=A0=91=20Swift=20=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...序与后序遍历序列构造二叉树.md | 102 +++++++++++++++++- 1 file changed, 100 insertions(+), 2 deletions(-) diff --git a/problems/0106.从中序与后序遍历序列构造二叉树.md b/problems/0106.从中序与后序遍历序列构造二叉树.md index 487e4f7d..59e0ba53 100644 --- a/problems/0106.从中序与后序遍历序列构造二叉树.md +++ b/problems/0106.从中序与后序遍历序列构造二叉树.md @@ -684,7 +684,7 @@ class Solution: root.right = self.buildTree(preorder_right, inorder_right) return root -``` +``` 106.从中序与后序遍历序列构造二叉树 @@ -716,7 +716,7 @@ class Solution: root.right = self.buildTree(inorder_right, postorder_right) return root -``` +``` ## Go @@ -816,6 +816,7 @@ var buildTree = function(preorder, inorder) { ## C 106 从中序与后序遍历序列构造二叉树 + ```c int linearSearch(int* arr, int arrSize, int key) { int i; @@ -847,6 +848,7 @@ struct TreeNode* buildTree(int* inorder, int inorderSize, int* postorder, int po ``` 105 从前序与中序遍历序列构造二叉树 + ```c struct TreeNode* buildTree(int* preorder, int preorderSize, int* inorder, int inorderSize){ // 递归结束条件：传入的数组大小为0 @@ -887,7 +889,103 @@ struct TreeNode* buildTree(int* preorder, int preorderSize, int* inorder, int in // 6.返回根节点 return root; } + ``` +## Swift + +105 从前序与中序遍历序列构造二叉树 + +```swift +class Solution { + func buildTree(_ preorder: [Int], _ inorder: [Int]) -> TreeNode? { + return helper(preorder: preorder, + preorderBegin: 0, + preorderEnd: preorder.count, + inorder: inorder, + inorderBegin: 0, + inorderEnd: inorder.count) + } + + func helper(preorder: [Int], preorderBegin: Int, preorderEnd: Int, inorder: [Int], inorderBegin: Int, inorderEnd: Int) -> TreeNode? { + if preorderBegin == preorderEnd { + return nil + } + + // 前序遍历数组的第一个元素作为分割点 + let rootValue = preorder[preorderBegin] + let root = TreeNode(rootValue) + + + if preorderEnd - preorderBegin == 1 { + return root + } + + var index = 0 // 从中序遍历数组中找到根节点的下标 + if let ind = inorder.firstIndex(of: rootValue) { + index = ind + } + + // 递归 + root.left = helper(preorder: preorder, + preorderBegin: preorderBegin + 1, + preorderEnd: preorderBegin + 1 + index - inorderBegin, + inorder: inorder, + inorderBegin: inorderBegin, + inorderEnd: index) + root.right = helper(preorder: preorder, + preorderBegin: preorderBegin + 1 + index - inorderBegin, + preorderEnd: preorderEnd, + inorder: inorder, + inorderBegin: index + 1, + inorderEnd: inorderEnd) + return root + } +} +``` + +106 从中序与后序遍历序列构造二叉树 + +```swift +class Solution_0106 { + func buildTree(inorder: [Int], inorderBegin: Int, inorderEnd: Int, postorder: [Int], postorderBegin: Int, postorderEnd: Int) -> TreeNode? { + if postorderEnd - postorderBegin < 1 { + return nil + } + + // 后序遍历数组的最后一个元素作为分割点 + let rootValue = postorder[postorderEnd - 1] + let root = TreeNode(rootValue) + + if postorderEnd - postorderBegin == 1 { + return root + } + + // 从中序遍历数组中找到根节点的下标 + var delimiterIndex = 0 + if let index = inorder.firstIndex(of: rootValue) { + delimiterIndex = index + } + + root.left = buildTree(inorder: inorder, + inorderBegin: inorderBegin, + inorderEnd: delimiterIndex, + postorder: postorder, + postorderBegin: postorderBegin, + postorderEnd: postorderBegin + (delimiterIndex - inorderBegin)) + + root.right = buildTree(inorder: inorder, + inorderBegin: delimiterIndex + 1, + inorderEnd: inorderEnd, + postorder: postorder, + postorderBegin: postorderBegin + (delimiterIndex - inorderBegin), + postorderEnd: postorderEnd - 1) + return root + } +} +``` + + + -----------------------
From 1f7f1617296bbb862b5ff6a265659ccd53659af4 Mon Sep 17 00:00:00 2001 From: Du Date: Sun, 9 Jan 2022 08:57:44 +0800 Subject: [PATCH 03/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0105.=20=E4=BB=8E?= =?UTF-8?q?=E5=89=8D=E5=BA=8F=E4=B8=8E=E4=B8=AD=E5=BA=8F=E9=81=8D=E5=8E=86?= =?UTF-8?q?=E5=BA=8F=E5=88=97=E6=9E=84=E9=80=A0=E4=BA=8C=E5=8F=89=E6=A0=91?= =?UTF-8?q?=E3=80=81106.=20=E4=BB=8E=E4=B8=AD=E5=BA=8F=E4=B8=8E=E5=90=8E?= =?UTF-8?q?=E5=BA=8F=E9=81=8D=E5=8E=86=E5=BA=8F=E5=88=97=E6=9E=84=E9=80=A0?= =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=A0=91=20Swift=20=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0106.从中序与后序遍历序列构造二叉树.md | 1 - 1 file changed, 1 deletion(-) diff --git a/problems/0106.从中序与后序遍历序列构造二叉树.md b/problems/0106.从中序与后序遍历序列构造二叉树.md index 59e0ba53..40d75983 100644 --- a/problems/0106.从中序与后序遍历序列构造二叉树.md +++ b/problems/0106.从中序与后序遍历序列构造二叉树.md @@ -889,7 +889,6 @@ struct TreeNode* buildTree(int* preorder, int preorderSize, int* inorder, int in // 6.返回根节点 return root; } - ``` ## Swift From a246b9b4e6dc344925259f64150400ddb7661ed4 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Sun, 9 Jan 2022 13:42:10 +0800 Subject: [PATCH 04/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=880203.=E7=A7=BB?= =?UTF-8?q?=E9=99=A4=E9=93=BE=E8=A1=A8=E5=85=83=E7=B4=A0.md=EF=BC=89?= =?UTF-8?q?=EF=BC=9A=E5=A2=9E=E5=8A=A0typescript=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0203.移除链表元素.md | 56 +++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/problems/0203.移除链表元素.md b/problems/0203.移除链表元素.md index 9d0ef91f..4e7bdd34 100644 --- a/problems/0203.移除链表元素.md +++ b/problems/0203.移除链表元素.md @@ -302,7 +302,63 @@ var removeElements = function(head, val) { }; ``` +TypeScript: + +版本一（在原链表上直接删除）： + +```typescript +/** + * Definition for singly-linked list. + * class ListNode { + * val: number + * next: ListNode | null + * constructor(val?: number, next?: ListNode | null) { + * this.val = (val===undefined ? 0 : val) + * this.next = (next===undefined ? null : next) + * } + * } + */ +function removeElements(head: ListNode | null, val: number): ListNode | null { + // 删除头部节点 + while (head !== null && head.val === val) { + head = head.next; + } + if (head === null) return head; + let pre: ListNode = head, cur: ListNode = head.next; + // 删除非头部节点 + while (cur) { + if (cur.val === val) { + pre.next = cur.next; + } else { + pre = pre.next; + } + cur = cur.next; + } + return head; +}; +``` + +版本二（虚拟头节点）： + +```typescript +function removeElements(head: ListNode | null, val: number): ListNode | null { + head = new ListNode(0, head); + let pre: ListNode = head, cur: ListNode = head.next; + // 删除非头部节点 + while (cur) { + if (cur.val === val) { + pre.next = cur.next; + } else { + pre = pre.next; + } + cur = cur.next; + } + return head.next; +}; +``` + Swift： + ```swift /** * Definition for singly-linked list. From d2904c2675ecc26f0b385f368c857eeb68d526fa Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Sun, 9 Jan 2022 18:19:46 +0800 Subject: [PATCH 05/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=880206.=E7=BF=BB?= =?UTF-8?q?=E8=BD=AC=E9=93=BE=E8=A1=A8.md=EF=BC=89=EF=BC=9A=E5=A2=9E?= =?UTF-8?q?=E5=8A=A0typescript=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0206.翻转链表.md | 48 +++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/problems/0206.翻转链表.md b/problems/0206.翻转链表.md index 13ed753c..941928ba 100644 --- a/problems/0206.翻转链表.md +++ b/problems/0206.翻转链表.md @@ -314,6 +314,54 @@ var reverseList = function(head) { }; ``` +TypeScript: + +```typescript +// 双指针法 +function reverseList(head: ListNode | null): ListNode | null { + let preNode: ListNode | null = null, + curNode: ListNode | null = head, + tempNode: ListNode | null; + while (curNode) { + tempNode = curNode.next; + curNode.next = preNode; + preNode = curNode; + curNode = tempNode; + } + return preNode; +}; + +// 递归（从前往后翻转） +function reverseList(head: ListNode | null): ListNode | null { + function recur(preNode: ListNode | null, curNode: ListNode | null): ListNode | null { + if (curNode === null) return preNode; + let tempNode: ListNode | null = curNode.next; + curNode.next = preNode; + preNode = curNode; + curNode = tempNode; + return recur(preNode, curNode); + } + return recur(null, head); +}; + +// 递归（从后往前翻转） +function reverseList(head: ListNode | null): ListNode | null { + if (head === null) return null; + let newHead: ListNode | null; + function recur(node: ListNode | null, preNode: ListNode | null): void { + if (node.next === null) { + newHead = node; + newHead.next = preNode; + } else { + recur(node.next, node); + node.next = preNode; + } + } + recur(head, null); + return newHead; +}; +``` + Ruby: ```ruby From c5c8fe50b4f101d495e4218722335f467e7e936c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9E=81=E5=AE=A2=E5=AD=A6=E4=BC=9F?= Date: Mon, 10 Jan 2022 15:02:55 +0800 Subject: [PATCH 06/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20101.=20=E5=AF=B9?= =?UTF-8?q?=E7=A7=B0=E4=BA=8C=E5=8F=89=E6=A0=91=20Swift=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0101.对称二叉树.md | 80 ++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) diff --git a/problems/0101.对称二叉树.md b/problems/0101.对称二叉树.md index b9dff99c..69bc41d3 100644 --- a/problems/0101.对称二叉树.md +++ b/problems/0101.对称二叉树.md @@ -574,7 +574,87 @@ var isSymmetric = function(root) { }; ``` +## Swift: +> 递归 +```swift +func isSymmetric(_ root: TreeNode?) -> Bool { + return _isSymmetric(root?.left, right: root?.right) +} +func _isSymmetric(_ left: TreeNode?, right: TreeNode?) -> Bool { + // 首先排除空节点情况 + if left == nil && right == nil { + return true + } else if left == nil && right != nil { + return false + } else if left != nil && right == nil { + return false + } else if left!.val != right!.val { + // 进而排除数值不相等的情况 + return false + } + + // left 和 right 都不为空, 且数值也相等就递归 + let inSide = _isSymmetric(left!.right, right: right!.left) + let outSide = _isSymmetric(left!.left, right: right!.right) + return inSide && outSide +} +``` + +> 迭代 - 使用队列 +```swift +func isSymmetric2(_ root: TreeNode?) -> Bool { + guard let root = root else { + return true + } + var queue = [TreeNode?]() + queue.append(root.left) + queue.append(root.right) + while !queue.isEmpty { + let left = queue.removeFirst() + let right = queue.removeFirst() + if left == nil && right == nil { + continue + } + if left == nil || right == nil || left?.val != right?.val { + return false + } + queue.append(left!.left) + queue.append(right!.right) + queue.append(left!.right) + queue.append(right!.left) + } + return true +} +``` + +> 迭代 - 使用栈 +```swift +func isSymmetric3(_ root: TreeNode?) -> Bool { + guard let root = root else { + return true + } + var stack = [TreeNode?]() + stack.append(root.left) + stack.append(root.right) + while !stack.isEmpty { + let left = stack.removeLast() + let right = stack.removeLast() + + if left == nil && right == nil { + continue + } + if left == nil || right == nil || left?.val != right?.val { + return false + } + stack.append(left!.left) + stack.append(right!.right) + stack.append(left!.right) + stack.append(right!.left) + } + return true +} +``` -----------------------
From b3711266156c2b8e25ac6e40b681842fefab9279 Mon Sep 17 00:00:00 2001 From: HanMengnan <1448189829@qq.com> Date: Tue, 11 Jan 2022 12:48:46 +0800 Subject: [PATCH 07/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=2034.=20=E5=9C=A8?= =?UTF-8?q?=E6=8E=92=E5=BA=8F=E6=95=B0=E7=BB=84=E4=B8=AD=E6=9F=A5=E6=89=BE?= =?UTF-8?q?=E5=85=83=E7=B4=A0=E7=9A=84=E7=AC=AC=E4=B8=80=E4=B8=AA=E5=92=8C?= =?UTF-8?q?=E6=9C=80=E5=90=8E=E4=B8=80=E4=B8=AA=E4=BD=8D=E7=BD=AE=20Go?= =?UTF-8?q?=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...元素的第一个和最后一个位置.md | 48 +++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md b/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md index 2b96e41b..3f9cd747 100644 --- a/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md +++ b/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md @@ -389,6 +389,54 @@ class Solution: ### Go ```go +func searchRange(nums []int, target int) []int { + leftBorder := searchLeftBorder(nums, target) + rightBorder := searchRightBorder(nums, target) + + if leftBorder == -2 || rightBorder == -2 { // 情况一 + return []int{-1, -1} + } else if rightBorder-leftBorder > 1 { // 情况三 + return []int{leftBorder + 1, rightBorder - 1} + } else { // 情况二 + return []int{-1, -1} + } +} + +func searchLeftBorder(nums []int, target int) int { + left, right := 0, len(nums)-1 + leftBorder := -2 // 记录一下leftBorder没有被赋值的情况 + for left <= right { + middle := (left + right) / 2 + if target == nums[middle] { + right = middle - 1 + // 左边界leftBorder更新 + leftBorder = right + } else if target > nums[middle] { + left = middle + 1 + } else { + right = middle - 1 + } + } + return leftBorder +} + +func searchRightBorder(nums []int, target int) int { + left, right := 0, len(nums)-1 + rightBorder := -2 // 记录一下rightBorder没有被赋值的情况 + for left <= right { + middle := (left + right) / 2 + if target == nums[middle] { + left = middle + 1 + // 右边界rightBorder更新 + rightBorder = left + } else if target > nums[middle] { + left = middle + 1 + } else { + right = middle - 1 + } + } + return rightBorder +} ``` ### JavaScript From dfa64fa37b9493cfdf41a431d06da3565e86b1c5 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Tue, 11 Jan 2022 13:59:52 +0800 Subject: [PATCH 08/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=880024.=E4=B8=A4?= =?UTF-8?q?=E4=B8=A4=E4=BA=A4=E6=8D=A2=E9=93=BE=E8=A1=A8=E4=B8=AD=E7=9A=84?= =?UTF-8?q?=E8=8A=82=E7=82=B9.md=EF=BC=89=EF=BC=9A=E5=A2=9E=E5=8A=A0typesc?= =?UTF-8?q?ript=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../0024.两两交换链表中的节点.md | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/problems/0024.两两交换链表中的节点.md b/problems/0024.两两交换链表中的节点.md index 01abc7b4..bf1fd5e1 100644 --- a/problems/0024.两两交换链表中的节点.md +++ b/problems/0024.两两交换链表中的节点.md @@ -250,6 +250,38 @@ var swapPairs = function (head) { }; ``` +TypeScript： + +```typescript +function swapPairs(head: ListNode | null): ListNode | null { + /** + * 初始状态： + * curNode -> node1 -> node2 -> tmepNode + * 转换过程： + * curNode -> node2 + * curNode -> node2 -> node1 + * curNode -> node2 -> node1 -> tempNode + * curNode = node1 + */ + let retNode: ListNode | null = new ListNode(0, head), + curNode: ListNode | null = retNode, + node1: ListNode | null = null, + node2: ListNode | null = null, + tempNode: ListNode | null = null; + + while (curNode && curNode.next && curNode.next.next) { + node1 = curNode.next; + node2 = curNode.next.next; + tempNode = node2.next; + curNode.next = node2; + node2.next = node1; + node1.next = tempNode; + curNode = node1; + } + return retNode.next; +}; +``` + Kotlin: ```kotlin From bc710f263f477d633798c9b357ce7f4178baddbf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9E=81=E5=AE=A2=E5=AD=A6=E4=BC=9F?= Date: Tue, 11 Jan 2022 14:45:40 +0800 Subject: [PATCH 09/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20104.=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=A0=91=E7=9A=84=E6=9C=80=E5=A4=A7=E6=B7=B1=E5=BA=A6?= =?UTF-8?q?=20Swift=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0104.二叉树的最大深度.md | 77 +++++++++++++++++++++++ 1 file changed, 77 insertions(+) diff --git a/problems/0104.二叉树的最大深度.md b/problems/0104.二叉树的最大深度.md index 85b41548..7038598b 100644 --- a/problems/0104.二叉树的最大深度.md +++ b/problems/0104.二叉树的最大深度.md @@ -653,5 +653,82 @@ int maxDepth(struct TreeNode* root){ } ``` +## Swift + +>二叉树最大深度 +```swift +// 递归 - 后序 +func maxDepth1(_ root: TreeNode?) -> Int { + return _maxDepth1(root) +} +func _maxDepth1(_ root: TreeNode?) -> Int { + if root == nil { + return 0 + } + let leftDepth = _maxDepth1(root!.left) + let rightDepth = _maxDepth1(root!.right) + return 1 + max(leftDepth, rightDepth) +} + +// 层序 +func maxDepth(_ root: TreeNode?) -> Int { + guard let root = root else { + return 0 + } + var queue = [TreeNode]() + queue.append(root) + var res: Int = 0 + while !queue.isEmpty { + res += 1 + for _ in 0 ..< queue.count { + let node = queue.removeFirst() + if let left = node.left { + queue.append(left) + } + if let right = node.right { + queue.append(right) + } + } + } + return res +} +``` + +>N叉树最大深度 +```swift +// 递归 +func maxDepth(_ root: Node?) -> Int { + guard let root = root else { + return 0 + } + var depth = 0 + for node in root.children { + depth = max(depth, maxDepth(node)) + } + return depth + 1 +} + +// 迭代-层序遍历 +func maxDepth1(_ root: Node?) -> Int { + guard let root = root else { + return 0 + } + var depth = 0 + var queue = [Node]() + queue.append(root) + while !queue.isEmpty { + let size = queue.count + depth += 1 + for _ in 0 ..< size { + let node = queue.removeFirst() + for child in node.children { + queue.append(child) + } + } + } + return depth +} +``` + -----------------------
From 0d2aacb400b106a0c1b3b72c769c7920951f5d05 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Tue, 11 Jan 2022 18:58:28 +0800 Subject: [PATCH 10/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=880019.=E5=88=A0?= =?UTF-8?q?=E9=99=A4=E9=93=BE=E8=A1=A8=E7=9A=84=E5=80=92=E6=95=B0=E7=AC=AC?= =?UTF-8?q?N=E4=B8=AA=E8=8A=82=E7=82=B9.md=EF=BC=89=EF=BC=9A=E5=A2=9E?= =?UTF-8?q?=E5=8A=A0typescript=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...0019.删除链表的倒数第N个节点.md | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/problems/0019.删除链表的倒数第N个节点.md b/problems/0019.删除链表的倒数第N个节点.md index e041937f..87ee6b12 100644 --- a/problems/0019.删除链表的倒数第N个节点.md +++ b/problems/0019.删除链表的倒数第N个节点.md @@ -181,7 +181,27 @@ var removeNthFromEnd = function(head, n) { return ret.next; }; ``` +TypeScript: + +```typescript +function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null { + let newHead: ListNode | null = new ListNode(0, head); + let slowNode: ListNode | null = newHead, + fastNode: ListNode | null = newHead; + for (let i = 0; i < n; i++) { + fastNode = fastNode.next; + } + while (fastNode.next) { + fastNode = fastNode.next; + slowNode = slowNode.next; + } + slowNode.next = slowNode.next.next; + return newHead.next; +}; +``` + Kotlin: + ```Kotlin fun removeNthFromEnd(head: ListNode?, n: Int): ListNode? { val pre = ListNode(0).apply { From 5b0b3daf2e65f88de0566aef47d74fa1a8b6aef2 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Tue, 11 Jan 2022 19:02:49 +0800 Subject: [PATCH 11/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0(0019.=E5=88=A0?= =?UTF-8?q?=E9=99=A4=E9=93=BE=E8=A1=A8=E7=9A=84=E5=80=92=E6=95=B0=E7=AC=AC?= =?UTF-8?q?N=E4=B8=AA=E8=8A=82=E7=82=B9.md)=EF=BC=9Atypescript=E7=89=88?= =?UTF-8?q?=E6=9C=AC=E5=A2=9E=E5=8A=A0=E6=96=B0=E8=A7=A3=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...0019.删除链表的倒数第N个节点.md | 44 +++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/problems/0019.删除链表的倒数第N个节点.md b/problems/0019.删除链表的倒数第N个节点.md index 87ee6b12..813e9b02 100644 --- a/problems/0019.删除链表的倒数第N个节点.md +++ b/problems/0019.删除链表的倒数第N个节点.md @@ -183,6 +183,8 @@ var removeNthFromEnd = function(head, n) { ``` TypeScript: +版本一（快慢指针法）： + ```typescript function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null { let newHead: ListNode | null = new ListNode(0, head); @@ -200,6 +202,48 @@ function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null { }; ``` +版本二（计算节点总数法）： + +```typescript +function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null { + let curNode: ListNode | null = head; + let listSize: number = 0; + while (curNode) { + curNode = curNode.next; + listSize++; + } + if (listSize === n) { + head = head.next; + } else { + curNode = head; + for (let i = 0; i < listSize - n - 1; i++) { + curNode = curNode.next; + } + curNode.next = curNode.next.next; + } + return head; +}; +``` + +版本三（递归倒退n法）： + +```typescript +function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null { + let newHead: ListNode | null = new ListNode(0, head); + let cnt = 0; + function recur(node) { + if (node === null) return; + recur(node.next); + cnt++; + if (cnt === n + 1) { + node.next = node.next.next; + } + } + recur(newHead); + return newHead.next; +}; +``` + Kotlin: ```Kotlin From c93867f0700e455615ca31b564253e1a8f00c603 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9E=81=E5=AE=A2=E5=AD=A6=E4=BC=9F?= Date: Wed, 12 Jan 2022 12:54:12 +0800 Subject: [PATCH 12/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20111.=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=A0=91=E7=9A=84=E6=9C=80=E5=B0=8F=E6=B7=B1=E5=BA=A6?= =?UTF-8?q?=20Swift=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0111.二叉树的最小深度.md | 43 +++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/problems/0111.二叉树的最小深度.md b/problems/0111.二叉树的最小深度.md index fc93d918..a439322a 100644 --- a/problems/0111.二叉树的最小深度.md +++ b/problems/0111.二叉树的最小深度.md @@ -404,8 +404,51 @@ var minDepth = function(root) { }; ``` +## Swift +> 递归 +```Swift +func minDepth(_ root: TreeNode?) -> Int { + guard let root = root else { + return 0 + } + if root.left == nil && root.right != nil { + return 1 + minDepth(root.right) + } + if root.left != nil && root.right == nil { + return 1 + minDepth(root.left) + } + return 1 + min(minDepth(root.left), minDepth(root.right)) +} +``` +> 迭代 +```Swift +func minDepth(_ root: TreeNode?) -> Int { + guard let root = root else { + return 0 + } + var res = 0 + var queue = [TreeNode]() + queue.append(root) + while !queue.isEmpty { + res += 1 + for _ in 0 ..< queue.count { + let node = queue.removeFirst() + if node.left == nil && node.right == nil { + return res + } + if let left = node.left { + queue.append(left) + } + if let right = node.right { + queue.append(right) + } + } + } + return res +} +``` -----------------------
From c6c39724089a07c5cdd809cca27dd46047fc998f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E6=9E=81=E5=AE=A2=E5=AD=A6=E4=BC=9F?= Date: Thu, 13 Jan 2022 14:08:26 +0800 Subject: [PATCH 13/13] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20222.=E5=AE=8C?= =?UTF-8?q?=E5=85=A8=E4=BA=8C=E5=8F=89=E6=A0=91=E7=9A=84=E8=8A=82=E7=82=B9?= =?UTF-8?q?=E4=B8=AA=E6=95=B0=20Swift=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../0222.完全二叉树的节点个数.md | 68 +++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/problems/0222.完全二叉树的节点个数.md b/problems/0222.完全二叉树的节点个数.md index 754a6094..8d38bace 100644 --- a/problems/0222.完全二叉树的节点个数.md +++ b/problems/0222.完全二叉树的节点个数.md @@ -522,5 +522,73 @@ int countNodes(struct TreeNode* root){ } ``` +## Swift: + +> 递归 +```swift +func countNodes(_ root: TreeNode?) -> Int { + return _countNodes(root) +} +func _countNodes(_ root: TreeNode?) -> Int { + guard let root = root else { + return 0 + } + let leftCount = _countNodes(root.left) + let rightCount = _countNodes(root.right) + return 1 + leftCount + rightCount +} +``` + +> 层序遍历 +```Swift +func countNodes(_ root: TreeNode?) -> Int { + guard let root = root else { + return 0 + } + var res = 0 + var queue = [TreeNode]() + queue.append(root) + while !queue.isEmpty { + let size = queue.count + for _ in 0 ..< size { + let node = queue.removeFirst() + res += 1 + if let left = node.left { + queue.append(left) + } + if let right = node.right { + queue.append(right) + } + } + } + return res +} +``` + +> 利用完全二叉树性质 +```Swift +func countNodes(_ root: TreeNode?) -> Int { + guard let root = root else { + return 0 + } + var leftNode = root.left + var rightNode = root.right + var leftDepth = 0 + var rightDepth = 0 + while leftNode != nil { + leftNode = leftNode!.left + leftDepth += 1 + } + while rightNode != nil { + rightNode = rightNode!.right + rightDepth += 1 + } + if leftDepth == rightDepth { + return (2 << leftDepth) - 1 + } + return countNodes(root.left) + countNodes(root.right) + 1 +} +``` + -----------------------