From c9dfda1c955c0665108d8aa7fc78b33d5edded99 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Sat, 2 Apr 2022 23:34:25 +0800 Subject: [PATCH 1/4] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=880047.=E5=85=A8?= =?UTF-8?q?=E6=8E=92=E5=88=97II.md=EF=BC=89=EF=BC=9A=E5=A2=9E=E5=8A=A0type?= =?UTF-8?q?script=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0047.全排列II.md | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/problems/0047.全排列II.md b/problems/0047.全排列II.md index 0cecac50..cce25cd9 100644 --- a/problems/0047.全排列II.md +++ b/problems/0047.全排列II.md @@ -292,6 +292,34 @@ var permuteUnique = function (nums) { ``` +### TypeScript + +```typescript +function permuteUnique(nums: number[]): number[][] { + nums.sort((a, b) => a - b); + const resArr: number[][] = []; + const usedArr: boolean[] = new Array(nums.length).fill(false); + backTracking(nums, []); + return resArr; + function backTracking(nums: number[], route: number[]): void { + if (route.length === nums.length) { + resArr.push(route.slice()); + return; + } + for (let i = 0, length = nums.length; i < length; i++) { + if (i > 0 && nums[i] === nums[i - 1] && usedArr[i - 1] === false) continue; + if (usedArr[i] === false) { + route.push(nums[i]); + usedArr[i] = true; + backTracking(nums, route); + usedArr[i] = false; + route.pop(); + } + } + } +}; +``` + ### Swift ```swift From 710e816012bb0198a5a42686e94d24b50aa68760 Mon Sep 17 00:00:00 2001 From: Steve2020 <841532108@qq.com> Date: Sun, 3 Apr 2022 11:26:52 +0800 Subject: [PATCH 2/4] =?UTF-8?q?=E4=BF=AE=E6=94=B9=EF=BC=8820201112?= =?UTF-8?q?=E5=9B=9E=E6=BA=AF=E5=91=A8=E6=9C=AB=E6=80=BB=E7=BB=93.md?= =?UTF-8?q?=EF=BC=89=EF=BC=9A=E8=A1=A5=E5=85=85=E5=88=86=E6=9E=90=E6=8E=92?= =?UTF-8?q?=E5=88=97=E9=97=AE=E9=A2=98=E6=97=B6=E9=97=B4=E5=A4=8D=E6=9D=82?= =?UTF-8?q?=E5=BA=A6?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/周总结/20201112回溯周末总结.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/problems/周总结/20201112回溯周末总结.md b/problems/周总结/20201112回溯周末总结.md index c61de4bb..af08097b 100644 --- a/problems/周总结/20201112回溯周末总结.md +++ b/problems/周总结/20201112回溯周末总结.md @@ -76,7 +76,7 @@ * 空间复杂度：$O(n)$，递归深度为n，所以系统栈所用空间为$O(n)$，每一层递归所用的空间都是常数级别，注意代码里的result和path都是全局变量，就算是放在参数里，传的也是引用，并不会新申请内存空间，最终空间复杂度为$O(n)$。 排列问题分析： -* 时间复杂度：$O(n!)$，这个可以从排列的树形图中很明显发现，每一层节点为n，第二层每一个分支都延伸了n-1个分支，再往下又是n-2个分支，所以一直到叶子节点一共就是 n * n-1 * n-2 * ..... 1 = n!。 +* 时间复杂度：$O(n!)$，这个可以从排列的树形图中很明显发现，每一层节点为n，第二层每一个分支都延伸了n-1个分支，再往下又是n-2个分支，所以一直到叶子节点一共就是 n * n-1 * n-2 * ..... 1 = n!。每个叶子节点都会有一个构造全排列填进数组的操作（对应的代码：`result.push_back(path)`），该操作的复杂度为$O(n)$。所以，最终时间复杂度为：n * n!，简化为$O(n!)$。 * 空间复杂度：$O(n)$，和子集问题同理。 组合问题分析： From e48336238d25eac775f1897ad85b9be551ba1e69 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E9=99=88=E6=A2=A6=E6=B4=81?= <3224935686@qq.com> Date: Sun, 3 Apr 2022 14:03:31 +0800 Subject: [PATCH 3/4] =?UTF-8?q?=E4=BF=AE=E6=94=B9=E4=BA=8C=E5=8F=89?= =?UTF-8?q?=E6=A0=91=E7=B3=BB=E5=88=9719=20=E4=BB=8E=E4=B8=AD=E5=BA=8F?= =?UTF-8?q?=E4=B8=8E=E5=90=8E=E5=BA=8F=E9=81=8D=E5=8E=86=E5=BA=8F=E5=88=97?= =?UTF-8?q?=E6=9E=84=E9=80=A0=E4=BA=8C=E5=8F=89=E6=A0=91JS=E7=89=88?= =?UTF-8?q?=E6=9C=AC=E5=8F=98=E9=87=8F=E5=90=8D=20preorder->inorder?= 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 | 2 +- 1 file changed, 1 insertion(+), 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 496de431..7ecca773 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 @@ -790,7 +790,7 @@ func findRootIndex(target int,inorder []int) int{ ```javascript var buildTree = function(inorder, postorder) { - if (!preorder.length) return null; + if (!inorder.length) return null; const rootVal = postorder.pop(); // 从后序遍历的数组中获取中间节点的值， 即数组最后一个值 let rootIndex = inorder.indexOf(rootVal); // 获取中间节点在中序遍历中的下标 const root = new TreeNode(rootVal); // 创建中间节点 From 328b447cf44335883ce51109859f6f801e2515a0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E9=99=88=E6=A2=A6=E6=B4=81?= <3224935686@qq.com> Date: Thu, 7 Apr 2022 21:16:00 +0800 Subject: [PATCH 4/4] =?UTF-8?q?=E6=B7=BB=E5=8A=A0(0108.=E5=B0=86=E6=9C=89?= =?UTF-8?q?=E5=BA=8F=E6=95=B0=E7=BB=84=E8=BD=AC=E6=8D=A2=E4=B8=BA=E4=BA=8C?= =?UTF-8?q?=E5=8F=89=E6=90=9C=E7=B4=A2=E6=A0=91.md):=E5=A2=9E=E5=8A=A0Java?= =?UTF-8?q?Script=E8=BF=AD=E4=BB=A3=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...将有序数组转换为二叉搜索树.md | 40 ++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/problems/0108.将有序数组转换为二叉搜索树.md b/problems/0108.将有序数组转换为二叉搜索树.md index bd5915fd..6ee3947b 100644 --- a/problems/0108.将有序数组转换为二叉搜索树.md +++ b/problems/0108.将有序数组转换为二叉搜索树.md @@ -355,6 +355,7 @@ func sortedArrayToBST(nums []int) *TreeNode { ``` ## JavaScript +递归 ```javascript var sortedArrayToBST = function (nums) { @@ -372,7 +373,44 @@ var sortedArrayToBST = function (nums) { return buildTree(nums, 0, nums.length - 1); }; ``` - +迭代 +```JavaScript +var sortedArrayToBST = function(nums) { + if(nums.length===0){ + return null; + } + let root=new TreeNode(0); //初始根节点 + let nodeQue=[root]; //放遍历的节点,并初始化 + let leftQue=[0]; //放左区间的下标,初始化 + let rightQue=[nums.length-1]; // 放右区间的下标 + + while(nodeQue.length){ + let curNode=nodeQue.pop(); + let left=leftQue.pop(); + let right=rightQue.pop(); + let mid=left+Math.floor((right-left)/2); + + curNode.val=nums[mid]; //将下标为mid的元素给中间节点 + +// 处理左区间 + if(left<=mid-1){ + curNode.left=new TreeNode(0); + nodeQue.push(curNode.left); + leftQue.push(left); + rightQue.push(mid-1); + } + +// 处理右区间 + if(right>=mid+1){ + curNode.right=new TreeNode(0); + nodeQue.push(curNode.right); + leftQue.push(mid+1); + rightQue.push(right); + } + } + return root; +}; +``` ## TypeScript ```typescript