From 20922e2f074d6d97b16f9ebffdc45f5fa5f03b3e Mon Sep 17 00:00:00 2001 From: jojoo15 <75017412+jojoo15@users.noreply.github.com> Date: Sun, 16 May 2021 14:09:37 +0200 Subject: [PATCH 01/12] =?UTF-8?q?Update=200257.=E4=BA=8C=E5=8F=89=E6=A0=91?= =?UTF-8?q?=E7=9A=84=E6=89=80=E6=9C=89=E8=B7=AF=E5=BE=84.md?= 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 | 27 +++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) 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 73387257..591ba81b 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 @@ -324,8 +324,31 @@ class Solution { ``` Python： +```Python +# class TreeNode: +# def __init__(self, val=0, left=None, right=None): +# self.val = val +# self.left = left +# self.right = right +class Solution: + def binaryTreePaths(self, root: TreeNode) -> List[str]: + path=[] + res=[] + def backtrace(root, path): + if not root:return + path.append(root.val) + if (not root.left)and (not root.right): + res.append(path[:]) + ways=[] + if root.left:ways.append(root.left) + if root.right:ways.append(root.right) + for way in ways: + backtrace(way,path) + path.pop() + backtrace(root,path) + return ["->".join(list(map(str,i))) for i in res] - +``` Go： @@ -335,4 +358,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From f576698668a182659ecc5ac08669d137e6310498 Mon Sep 17 00:00:00 2001 From: jojoo15 <75017412+jojoo15@users.noreply.github.com> Date: Sun, 16 May 2021 15:14:24 +0200 Subject: [PATCH 02/12] =?UTF-8?q?Update=200404.=E5=B7=A6=E5=8F=B6=E5=AD=90?= =?UTF-8?q?=E4=B9=8B=E5=92=8C.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit python version added --- problems/0404.左叶子之和.md | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/problems/0404.左叶子之和.md b/problems/0404.左叶子之和.md index 0290dccd..5f303196 100644 --- a/problems/0404.左叶子之和.md +++ b/problems/0404.左叶子之和.md @@ -205,8 +205,25 @@ class Solution { Python： - - +```Python +**递归** +# Definition for a binary tree node. +# class TreeNode: +# def __init__(self, val=0, left=None, right=None): +# self.val = val +# self.left = left +# self.right = right +class Solution: + def sumOfLeftLeaves(self, root: TreeNode) -> int: + self.res=0 + def areleftleaves(root): + if not root:return + if root.left and (not root.left.left) and (not root.left.right):self.res+=root.left.val + areleftleaves(root.left) + areleftleaves(root.right) + areleftleaves(root) + return self.res +``` Go： From ad538d8e48e21d5c0910e47912c6c3213379ac15 Mon Sep 17 00:00:00 2001 From: youngyangyang04 <826123027@qq.com> Date: Sun, 16 May 2021 20:06:05 +0800 Subject: [PATCH 03/12] =?UTF-8?q?=E4=BF=AE=E6=AD=A3Markdown=E4=BB=A3?= =?UTF-8?q?=E7=A0=81=E5=9D=97=E8=AF=AD=E6=B3=95?= 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 | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) 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 73387257..29bcdf41 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 @@ -77,7 +77,7 @@ if (cur->left == NULL && cur->right == NULL) { 这里我们先使用vector结构的path容器来记录路径，那么终止处理逻辑如下： -``` +```C++ if (cur->left == NULL && cur->right == NULL) { // 遇到叶子节点 string sPath; for (int i = 0; i < path.size() - 1; i++) { // 将path里记录的路径转为string格式 @@ -113,7 +113,7 @@ if (cur->right) { 那么回溯要怎么回溯呢，一些同学会这么写，如下： -``` +```C++ if (cur->left) { traversal(cur->left, path, result); } @@ -129,7 +129,7 @@ path.pop_back(); 那么代码应该这么写： -``` +```C++ if (cur->left) { traversal(cur->left, path, result); path.pop_back(); // 回溯 @@ -335,4 +335,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From cc303e65eac9ea78879d09d50ea6212445fb3936 Mon Sep 17 00:00:00 2001 From: youngyangyang04 <826123027@qq.com> Date: Sun, 16 May 2021 21:33:15 +0800 Subject: [PATCH 04/12] =?UTF-8?q?=E6=9B=B4=E6=96=B00383.=E8=B5=8E=E9=87=91?= =?UTF-8?q?=E4=BF=A1=E7=9A=84=E6=8E=92=E7=89=88=E6=A0=BC=E5=BC=8F?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0383.赎金信.md | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/problems/0383.赎金信.md b/problems/0383.赎金信.md index 742bfdc3..2f7ae4d8 100644 --- a/problems/0383.赎金信.md +++ b/problems/0383.赎金信.md @@ -26,7 +26,7 @@ canConstruct("a", "b") -> false canConstruct("aa", "ab") -> false canConstruct("aa", "aab") -> true -# 思路 +## 思路 这道题目和[242.有效的字母异位词](https://mp.weixin.qq.com/s/vM6OszkM6L1Mx2Ralm9Dig)很像，[242.有效的字母异位词](https://mp.weixin.qq.com/s/vM6OszkM6L1Mx2Ralm9Dig)相当于求 字符串a 和 字符串b 是否可以相互组成 ，而这道题目是求 字符串a能否组成字符串b，而不用管字符串b 能不能组成字符串a。 @@ -36,7 +36,7 @@ canConstruct("aa", "aab") -> true * 第二点 “你可以假设两个字符串均只含有小写字母。” *说明只有小写字母*，这一点很重要 -# 暴力解法 +## 暴力解法 那么第一个思路其实就是暴力枚举了，两层for循环，不断去寻找，代码如下： @@ -67,7 +67,7 @@ public: 这里时间复杂度是比较高的，而且里面还有一个字符串删除也就是erase的操作，也是费时的，当然这段代码也可以过这道题。 -# 哈希解法 +## 哈希解法 因为题目所只有小写字母，那可以采用空间换取时间的哈希策略， 用一个长度为26的数组还记录magazine里字母出现的次数。 @@ -105,8 +105,6 @@ public: - - ## 其他语言版本 From 0ca23b650186636a10943fa812fba6a799a0070e Mon Sep 17 00:00:00 2001 From: youngyangyang04 <826123027@qq.com> Date: Sun, 16 May 2021 21:37:48 +0800 Subject: [PATCH 05/12] =?UTF-8?q?=E6=9B=B4=E6=96=B0=200216.=E7=BB=84?= =?UTF-8?q?=E5=90=88=E6=80=BB=E5=92=8CIII=20Markdown=E4=BB=A3=E7=A0=81?= =?UTF-8?q?=E5=9D=97=E8=AF=AD=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0216.组合总和III.md | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/problems/0216.组合总和III.md b/problems/0216.组合总和III.md index 21230e0f..bcb443e3 100644 --- a/problems/0216.组合总和III.md +++ b/problems/0216.组合总和III.md @@ -94,7 +94,7 @@ void backtracking(int targetSum, int k, int sum, int startIndex) 所以 终止代码如下： -``` +```C++ if (path.size() == k) { if (sum == targetSum) result.push_back(path); return; // 如果path.size() == k 但sum != targetSum 直接返回 @@ -112,7 +112,7 @@ if (path.size() == k) { 代码如下： -``` +```C++ for (int i = startIndex; i <= 9; i++) { sum += i; path.push_back(i); @@ -126,7 +126,7 @@ for (int i = startIndex; i <= 9; i++) { 参照[关于回溯算法，你该了解这些！](https://mp.weixin.qq.com/s/gjSgJbNbd1eAA5WkA-HeWw)中的模板，不难写出如下C++代码： -``` +```C++ class Solution { private: vector> result; // 存放结果集 @@ -273,4 +273,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From 2839bd0fc92ad1c23714d313e8178c2d6fd8b95d Mon Sep 17 00:00:00 2001 From: jojoo15 <75017412+jojoo15@users.noreply.github.com> Date: Sun, 16 May 2021 15:55:52 +0200 Subject: [PATCH 06/12] =?UTF-8?q?Update=200513.=E6=89=BE=E6=A0=91=E5=B7=A6?= =?UTF-8?q?=E4=B8=8B=E8=A7=92=E7=9A=84=E5=80=BC.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0513.找树左下角的值.md | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/problems/0513.找树左下角的值.md b/problems/0513.找树左下角的值.md index ac21dc68..44096a29 100644 --- a/problems/0513.找树左下角的值.md +++ b/problems/0513.找树左下角的值.md @@ -274,8 +274,28 @@ class Solution { Python： - - +```python +//递归法 +# Definition for a binary tree node. +# class TreeNode: +# def __init__(self, val=0, left=None, right=None): +# self.val = val +# self.left = left +# self.right = right +class Solution: + def findBottomLeftValue(self, root: TreeNode) -> int: + depth=0 + self.res=[] + def level(root,depth): + if not root:return + if depth==len(self.res): + self.res.append([]) + self.res[depth].append(root.val) + level(root.left,depth+1) + level(root.right,depth+1) + level(root,depth) + return self.res[-1][0] +``` Go： @@ -285,4 +305,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From 6c95ec5ebde5cb202d02e5ae7ce5395c8bacda06 Mon Sep 17 00:00:00 2001 From: LiangDazhu <42199191+LiangDazhu@users.noreply.github.com> Date: Sun, 16 May 2021 23:11:23 +0800 Subject: [PATCH 07/12] =?UTF-8?q?Update=200860.=E6=9F=A0=E6=AA=AC=E6=B0=B4?= =?UTF-8?q?=E6=89=BE=E9=9B=B6.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Added python version code --- problems/0860.柠檬水找零.md | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/problems/0860.柠檬水找零.md b/problems/0860.柠檬水找零.md index bf8a3776..052bcdb1 100644 --- a/problems/0860.柠檬水找零.md +++ b/problems/0860.柠檬水找零.md @@ -156,7 +156,30 @@ class Solution { ``` Python： +```python +class Solution: + def lemonadeChange(self, bills: List[int]) -> bool: + five, ten, twenty = 0, 0, 0 + for bill in bills: + if bill == 5: + five += 1 + elif bill == 10: + if five < 1: return False + five -= 1 + ten += 1 + else: + if ten > 0 and five > 0: + ten -= 1 + five -= 1 + twenty += 1 + elif five > 2: + five -= 3 + twenty += 1 + else: + return False + return True +``` Go： @@ -167,4 +190,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From 4344d4bd26b3974d06852788b98226a8f1690b10 Mon Sep 17 00:00:00 2001 From: LiangDazhu <42199191+LiangDazhu@users.noreply.github.com> Date: Mon, 17 May 2021 00:41:27 +0800 Subject: [PATCH 08/12] =?UTF-8?q?Update=200406.=E6=A0=B9=E6=8D=AE=E8=BA=AB?= =?UTF-8?q?=E9=AB=98=E9=87=8D=E5=BB=BA=E9=98=9F=E5=88=97.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Added python version code --- problems/0406.根据身高重建队列.md | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/problems/0406.根据身高重建队列.md b/problems/0406.根据身高重建队列.md index 2ef0a2fd..c404ec8d 100644 --- a/problems/0406.根据身高重建队列.md +++ b/problems/0406.根据身高重建队列.md @@ -211,7 +211,18 @@ class Solution { ``` Python： - +```python +class Solution: + def reconstructQueue(self, people: List[List[int]]) -> List[List[int]]: + people.sort(key=lambda x: (x[0], -x[1]), reverse=True) + que = [] + for p in people: + if p[1] > len(que): + que.append(p) + else: + que.insert(p[1], p) + return que +``` Go： @@ -222,4 +233,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From 0a395dbed448dbc815806b12e48de74c131ee1e2 Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Mon, 17 May 2021 10:49:35 +0800 Subject: [PATCH 09/12] =?UTF-8?q?Update=201143.=E6=9C=80=E9=95=BF=E5=85=AC?= =?UTF-8?q?=E5=85=B1=E5=AD=90=E5=BA=8F=E5=88=97.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/1143.最长公共子序列.md | 30 +++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/problems/1143.最长公共子序列.md b/problems/1143.最长公共子序列.md index 19f4cc72..961924c8 100644 --- a/problems/1143.最长公共子序列.md +++ b/problems/1143.最长公共子序列.md @@ -166,6 +166,34 @@ class Solution: Go： +```Go +func longestCommonSubsequence(text1 string, text2 string) int { + t1 := len(text1) + t2 := len(text2) + dp:=make([][]int,t1+1) + for i:=range dp{ + dp[i]=make([]int,t2+1) + } + + for i := 1; i <= t1; i++ { + for j := 1; j <=t2; j++ { + if text1[i-1]==text2[j-1]{ + dp[i][j]=dp[i-1][j-1]+1 + }else{ + dp[i][j]=max(dp[i-1][j],dp[i][j-1]) + } + } + } + return dp[t1][t2] +} + +func max(a,b int)int { + if a>b{ + return a + } + return b +} +``` @@ -174,4 +202,4 @@ Go： * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频：[代码随想录](https://space.bilibili.com/525438321) * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
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From 1c7250407c665f83fa94e7358852bb42a1d0d4ec Mon Sep 17 00:00:00 2001 From: weikunkun Date: Mon, 17 May 2021 12:15:50 +0800 Subject: [PATCH 10/12] =?UTF-8?q?=E6=B7=BB=E5=8A=A00714.=E4=B9=B0=E5=8D=96?= =?UTF-8?q?=E8=82=A1=E7=A5=A8=E7=9A=84=E6=9C=80=E4=BD=B3=E6=97=B6=E6=9C=BA?= =?UTF-8?q?=E5=90=AB=E6=89=8B=E7=BB=AD=E8=B4=B9=20Java=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...佳时机含手续费（动态规划）.md | 41 +++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md b/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md index 3926643d..a239e5d8 100644 --- a/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md +++ b/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md @@ -95,7 +95,48 @@ public: Java： +```java +/** + * 卖出时支付手续费 + * @param prices + * @param fee + * @return + */ +public int maxProfit(int[] prices, int fee) { + int len = prices.length; + // 0 : 持股（买入） + // 1 : 不持股（售出） + // dp 定义第i天持股/不持股 所得最多现金 + int[][] dp = new int[len][2]; + dp[0][0] = -prices[0]; + for (int i = 1; i < len; i++) { + dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] - prices[i]); + dp[i][1] = Math.max(dp[i - 1][0] + prices[i] - fee, dp[i - 1][1]); + } + return Math.max(dp[len - 1][0], dp[len - 1][1]); +} +/** + * 买入时支付手续费 + * @param prices + * @param fee + * @return + */ +public int maxProfit(int[] prices, int fee) { + int len = prices.length; + // 0 : 持股（买入） + // 1 : 不持股（售出） + // dp 定义第i天持股/不持股 所得最多现金 + int[][] dp = new int[len][2]; + // 考虑买入的时候就支付手续费 + dp[0][0] = -prices[0] - fee; + for (int i = 1; i < len; i++) { + dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] - prices[i] - fee); + dp[i][1] = Math.max(dp[i - 1][0] + prices[i], dp[i - 1][1]); + } + return Math.max(dp[len - 1][0], dp[len - 1][1]); +} +``` Python： From dae5f4debe408c2fce12226a5e7b986d116df094 Mon Sep 17 00:00:00 2001 From: "Zhen Liu (Ramsey)" <416034116@qq.com> Date: Mon, 17 May 2021 01:18:28 -0300 Subject: [PATCH 11/12] =?UTF-8?q?Update=20=E9=9D=A2=E8=AF=95=E9=A2=9802.07?= =?UTF-8?q?.=E9=93=BE=E8=A1=A8=E7=9B=B8=E4=BA=A4=20Java=20=E7=89=88?= =?UTF-8?q?=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 代码经过测试 beats 98% submission, 完全follow Carl's C++版本的全部逻辑，稍作修改并加上了注释！辛苦啦！谢谢 --- problems/面试题02.07.链表相交.md | 58 ++++++++++++++++++++++++- 1 file changed, 57 insertions(+), 1 deletion(-) diff --git a/problems/面试题02.07.链表相交.md b/problems/面试题02.07.链表相交.md index 97045ed2..493438d7 100644 --- a/problems/面试题02.07.链表相交.md +++ b/problems/面试题02.07.链表相交.md @@ -92,7 +92,63 @@ public: Java： - +```Java +/** + * Definition for singly-linked list. + * public class ListNode { + * int val; + * ListNode next; + * ListNode(int x) { + * val = x; + * next = null; + * } + * } + */ +public class Solution { + public ListNode getIntersectionNode(ListNode headA, ListNode headB) { + ListNode curA = headA; + ListNode curB = headB; + int lenA = 0, lenB = 0; + while (curA != null) { // 求链表A的长度 + lenA++; + curA = curA.next; + } + while (curB != null) { // 求链表B的长度 + lenB++; + curB = curB.next; + } + curA = headA; + curB = headB; + // 让curA为最长链表的头，lenA为其长度 + if (lenB > lenA) { + //1. swap (lenA, lenB); + int tmpLen = lenA; + lenA = lenB; + lenB = tmpLen; + //2. swap (curA, curB); + ListNode tmpNode = curA; + curA = curB; + curB = tmpNode; + } + // 求长度差 + int gap = lenA - lenB; + // 让curA和curB在同一起点上（末尾位置对齐） + while (gap-- > 0) { + curA = curA.next; + } + // 遍历curA 和 curB，遇到相同则直接返回 + while (curA != null) { + if (curA == curB) { + return curA; + } + curA = curA.next; + curB = curB.next; + } + return null; + } + +} +``` Python： From 6917b61c586adc2b19b044d2057a75a04a18362b Mon Sep 17 00:00:00 2001 From: QuinnDK <39618652+QuinnDK@users.noreply.github.com> Date: Mon, 17 May 2021 15:50:36 +0800 Subject: [PATCH 12/12] =?UTF-8?q?Update=200142.=E7=8E=AF=E5=BD=A2=E9=93=BE?= =?UTF-8?q?=E8=A1=A8II.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0142.环形链表II.md | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/problems/0142.环形链表II.md b/problems/0142.环形链表II.md index 7556b854..b3a53c07 100644 --- a/problems/0142.环形链表II.md +++ b/problems/0142.环形链表II.md @@ -234,6 +234,29 @@ class Solution: ``` Go： +```func detectCycle(head *ListNode) *ListNode { + if head ==nil{ + return head + } + slow:=head + fast:=head.Next + + for fast!=nil&&fast.Next!=nil{ + if fast==slow{ + slow=head + fast=fast.Next + for fast!=slow { + fast=fast.Next + slow=slow.Next + } + return slow + } + fast=fast.Next.Next + slow=slow.Next + } + return nil +} +``` -----------------------