From 530422fa3ecf004d27f45552e909506947992902 Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Mon, 23 May 2022 10:04:15 +0800 Subject: [PATCH 1/6] =?UTF-8?q?0416.=E5=88=86=E5=89=B2=E7=AD=89=E5=92=8C?= =?UTF-8?q?=E5=AD=90=E9=9B=86=20=E6=96=B0=E5=A2=9E=20typescript=20?= =?UTF-8?q?=E8=A7=A3=E6=B3=95=E4=BB=A3=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0416.分割等和子集.md | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/problems/0416.分割等和子集.md b/problems/0416.分割等和子集.md index 6e93ae8e..01ea825e 100644 --- a/problems/0416.分割等和子集.md +++ b/problems/0416.分割等和子集.md @@ -416,7 +416,24 @@ var canPartition = function(nums) { }; ``` +TypeScript: +```ts +function canPartition(nums: number[]): boolean { + const sum: number = nums.reduce((a: number, b: number): number => a + b); + if (sum % 2 === 1) return false; + const target: number = sum / 2; + // dp[j]表示容量（总数和）为j的背包所能装下的数（下标[0, i]之间任意取）的总和（<= 容量）的最大值 + const dp: number[] = new Array(target + 1).fill(0); + const n: number = nums.length; + for (let i: number = 0; i < n; i++) { + for (let j: number = target; j >= nums[i]; j--) { + dp[j] = Math.max(dp[j], dp[j - nums[i]] + nums[i]); + } + } + return dp[target] === target; +}; +``` ----------------------- From 8f9c8e5fb1f9d89830b92a06f1fc59d97fd84772 Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Mon, 23 May 2022 10:10:48 +0800 Subject: [PATCH 2/6] =?UTF-8?q?1049.=E6=9C=80=E5=90=8E=E4=B8=80=E5=9D=97?= =?UTF-8?q?=E7=9F=B3=E5=A4=B4=E9=87=8D=E9=87=8F=20=E6=96=B0=E5=A2=9Etypesc?= =?UTF-8?q?ript=E7=89=88=E6=9C=AC=E4=BB=A3=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/1049.最后一块石头的重量II.md | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/problems/1049.最后一块石头的重量II.md b/problems/1049.最后一块石头的重量II.md index ee0ddef2..8d3eeb3b 100644 --- a/problems/1049.最后一块石头的重量II.md +++ b/problems/1049.最后一块石头的重量II.md @@ -277,5 +277,23 @@ var lastStoneWeightII = function (stones) { }; ``` +TypeScript版本 + +```ts +function lastStoneWeightII(stones: number[]): number { + const sum: number = stones.reduce((a: number, b:number): number => a + b); + const target: number = Math.floor(sum / 2); + const n: number = stones.length; + // dp[j]表示容量（总数和）为j的背包所能装下的数（下标[0, i]之间任意取）的总和（<= 容量）的最大值 + const dp: number[] = new Array(target + 1).fill(0); + for (let i: number = 0; i < n; i++ ) { + for (let j: number = target; j >= stones[i]; j--) { + dp[j] = Math.max(dp[j], dp[j - stones[i]] + stones[i]); + } + } + return sum - dp[target] - dp[target]; +}; +``` + -----------------------
From ffc91f1f1ca6099af747c77c5cdbfc21125fc140 Mon Sep 17 00:00:00 2001 From: Luo <82520819+Jerry-306@users.noreply.github.com> Date: Mon, 23 May 2022 10:20:08 +0800 Subject: [PATCH 3/6] =?UTF-8?q?0494.=E7=9B=AE=E6=A0=87=E5=92=8C=20?= =?UTF-8?q?=E6=96=B0=E5=A2=9Etypescript=E7=89=88=E6=9C=AC=E4=BB=A3?= =?UTF-8?q?=E7=A0=81?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0494.目标和.md | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/problems/0494.目标和.md b/problems/0494.目标和.md index 99b76834..929b97d4 100644 --- a/problems/0494.目标和.md +++ b/problems/0494.目标和.md @@ -351,6 +351,28 @@ const findTargetSumWays = (nums, target) => { }; ``` +TypeScript: + +```ts +function findTargetSumWays(nums: number[], target: number): number { + // 把数组分成两个组合left, right.left + right = sum, left - right = target. + const sum: number = nums.reduce((a: number, b: number): number => a + b); + if ((sum + target) % 2 || Math.abs(target) > sum) return 0; + const left: number = (sum + target) / 2; + + // 将问题转化为装满容量为left的背包有多少种方法 + // dp[i]表示装满容量为i的背包有多少种方法 + const dp: number[] = new Array(left + 1).fill(0); + dp[0] = 1; // 装满容量为0的背包有1种方法（什么也不装） + for (let i: number = 0; i < nums.length; i++) { + for (let j: number = left; j >= nums[i]; j--) { + dp[j] += dp[j - nums[i]]; + } + } + return dp[left]; +}; +``` + ----------------------- From 282cdc2b44b755098d223d0f9c8bd36bf0e85959 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Mon, 23 May 2022 11:18:04 +0800 Subject: [PATCH 4/6] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=881365.=E6=9C=89?= =?UTF-8?q?=E5=A4=9A=E5=B0=91=E5=B0=8F=E4=BA=8E=E5=BD=93=E5=89=8D=E6=95=B0?= =?UTF-8?q?=E5=AD=97=E7=9A=84=E6=95=B0=E5=AD=97.md=EF=BC=89=EF=BC=9A?= =?UTF-8?q?=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 --- ...65.有多少小于当前数字的数字.md | 40 +++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/problems/1365.有多少小于当前数字的数字.md b/problems/1365.有多少小于当前数字的数字.md index 78fa84c0..ce1e77df 100644 --- a/problems/1365.有多少小于当前数字的数字.md +++ b/problems/1365.有多少小于当前数字的数字.md @@ -217,6 +217,46 @@ var smallerNumbersThanCurrent = function(nums) { }; ``` +TypeScript: + +> 暴力法： + +```typescript +function smallerNumbersThanCurrent(nums: number[]): number[] { + const length: number = nums.length; + const resArr: number[] = []; + for (let i = 0; i < length; i++) { + let count: number = 0; + for (let j = 0; j < length; j++) { + if (nums[j] < nums[i]) { + count++; + } + } + resArr[i] = count; + } + return resArr; +}; +``` + +> 排序+hash + +```typescript +function smallerNumbersThanCurrent(nums: number[]): number[] { + const length: number = nums.length; + const sortedArr: number[] = [...nums]; + sortedArr.sort((a, b) => a - b); + const hashMap: Map = new Map(); + for (let i = length - 1; i >= 0; i--) { + hashMap.set(sortedArr[i], i); + } + const resArr: number[] = []; + for (let i = 0; i < length; i++) { + resArr[i] = hashMap.get(nums[i]); + } + return resArr; +}; +``` + ----------------------- From f83d5edb6ebf5cd6de1eabba51a246a921f94e1b Mon Sep 17 00:00:00 2001 From: ZongqinWang <1722249371@qq.com> Date: Mon, 23 May 2022 19:14:45 +0800 Subject: [PATCH 5/6] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200222.=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.md=20Scala=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 | 63 +++++++++++++++++++ 1 file changed, 63 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 ba7acc5a..746d45cc 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 @@ -646,5 +646,68 @@ func countNodes(_ root: TreeNode?) -> Int { } ``` +## Scala + +递归: +```scala +object Solution { + def countNodes(root: TreeNode): Int = { + if(root == null) return 0 + 1 + countNodes(root.left) + countNodes(root.right) + } +} +``` + +层序遍历: +```scala +object Solution { + import scala.collection.mutable + def countNodes(root: TreeNode): Int = { + if (root == null) return 0 + val queue = mutable.Queue[TreeNode]() + var node = 0 + queue.enqueue(root) + while (!queue.isEmpty) { + val len = queue.size + for (i <- 0 until len) { + node += 1 + val curNode = queue.dequeue() + if (curNode.left != null) queue.enqueue(curNode.left) + if (curNode.right != null) queue.enqueue(curNode.right) + } + } + node + } +} +``` + +利用完全二叉树性质: +```scala +object Solution { + def countNodes(root: TreeNode): Int = { + if (root == null) return 0 + var leftNode = root.left + var rightNode = root.right + // 向左向右往下探 + var leftDepth = 0 + while (leftNode != null) { + leftDepth += 1 + leftNode = leftNode.left + } + var rightDepth = 0 + while (rightNode != null) { + rightDepth += 1 + rightNode = rightNode.right + } + // 如果相等就是一个满二叉树 + if (leftDepth == rightDepth) { + return (2 << leftDepth) - 1 + } + // 如果不相等就不是一个完全二叉树，继续向下递归 + countNodes(root.left) + countNodes(root.right) + 1 + } +} +``` + -----------------------
From 45a3c91a7a954947d6b7373bee876d2f498e26bd Mon Sep 17 00:00:00 2001 From: ZongqinWang <1722249371@qq.com> Date: Mon, 23 May 2022 19:49:18 +0800 Subject: [PATCH 6/6] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200257.=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=A0=91=E7=9A=84=E6=89=80=E6=9C=89=E8=B7=AF=E5=BE=84?= =?UTF-8?q?.md=20Scala=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0257.二叉树的所有路径.md | 30 +++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/problems/0257.二叉树的所有路径.md b/problems/0257.二叉树的所有路径.md index 1362897c..70a3c66f 100644 --- a/problems/0257.二叉树的所有路径.md +++ b/problems/0257.二叉树的所有路径.md @@ -702,5 +702,35 @@ func binaryTreePaths(_ root: TreeNode?) -> [String] { } ``` +Scala: + +递归: +```scala +object Solution { + import scala.collection.mutable.ListBuffer + def binaryTreePaths(root: TreeNode): List[String] = { + val res = ListBuffer[String]() + def traversal(curNode: TreeNode, path: ListBuffer[Int]): Unit = { + path.append(curNode.value) + if (curNode.left == null && curNode.right == null) { + res.append(path.mkString("->")) // mkString函数: 将数组的所有值按照指定字符串拼接 + return // 处理完可以直接return + } + + if (curNode.left != null) { + traversal(curNode.left, path) + path.remove(path.size - 1) + } + if (curNode.right != null) { + traversal(curNode.right, path) + path.remove(path.size - 1) + } + } + traversal(root, ListBuffer[Int]()) + res.toList + } +} +``` + -----------------------