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 1/9] =?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 2/9] =?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 3/9] =?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 4/9] =?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 5/9] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20104.=E4=BA=8C=E5=8F=89?= =?UTF-8?q?=E6=A0=91=E7=9A=84=E6=9C=80=E5=A4=A7=E6=B7=B1=E5=BA=A6=20Swift?= =?UTF-8?q?=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 6/9] =?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 7/9] =?UTF-8?q?=E6=B7=BB=E5=8A=A0(0019.=E5=88=A0=E9=99=A4?= =?UTF-8?q?=E9=93=BE=E8=A1=A8=E7=9A=84=E5=80=92=E6=95=B0=E7=AC=ACN?= =?UTF-8?q?=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 8/9] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20111.=E4=BA=8C=E5=8F=89?= =?UTF-8?q?=E6=A0=91=E7=9A=84=E6=9C=80=E5=B0=8F=E6=B7=B1=E5=BA=A6=20Swift?= =?UTF-8?q?=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 9/9] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20222.=E5=AE=8C=E5=85=A8?= =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=A0=91=E7=9A=84=E8=8A=82=E7=82=B9=E4=B8=AA?= =?UTF-8?q?=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 +} +``` + -----------------------