Merge pull request #1 from doocs/master

update

Author: zhkmxx9302013

README.md

@@ -1,17 +1,17 @@
 <p align="center">
-  <a href="https://github.com/doocs/leetcode"><img src="http://p9ucdlghd.bkt.clouddn.com/leetcode-github.png" alt="LeetCode-GitHub"></a>
+  <a href="https://github.com/doocs/leetcode"><img src="http://p9ucdlghd.bkt.clouddn.com/leetcode-github-yanglbme.png" alt="LeetCode-GitHub-yanglbme"></a>
 </p>
 
 <p align="center">
-  <a href="https://github.com/doocs/leetcode"><img src="https://img.shields.io/badge/Lang-Java%2FPython%2FJS%2FCPP%2FGo%2F...-blue.svg" alt="Language"></a>
+  <a href="https://github.com/doocs/leetcode"><img src="https://img.shields.io/badge/lang-Java%2FPython%2FRuby%2FCPP%2FJS%2FGo...-blue.svg" alt="Language"></a>
   <a href="http://makeapullrequest.com"><img src="https://img.shields.io/badge/PRs-Welcome-brightgreen.svg" alt="PRs Welcome"></a>
   <a href="https://github.com/doocs/leetcode/issues"><img src="https://img.shields.io/github/issues/doocs/leetcode.svg" alt="issues"></a>
   <a href="https://github.com/doocs/leetcode/stargazers"><img src="https://img.shields.io/github/stars/doocs/leetcode.svg" alt="stars"></a>
   <a href="https://github.com/doocs/leetcode/network/members"><img src="https://img.shields.io/github/forks/doocs/leetcode.svg" alt="forks"></a>
 </p>
 
 ## Introduction
-Complete solutions to Leetcode problems, updated daily.
+Complete [solutions](https://github.com/doocs/leetcode/tree/master/solution) to Leetcode problems, [updated daily](https://github.com/doocs/leetcode/projects/1).
 
 ## Solution List
 
@@ -21,22 +21,30 @@ Complete solutions to Leetcode problems, updated daily.
 |---|---|---|
 | 001 | [Two Sum](https://github.com/doocs/leetcode/tree/master/solution/001.Two%20Sum) | `Array`, `Hash Table` |
 | 007 | [Reverse Integer](https://github.com/doocs/leetcode/tree/master/solution/007.Reverse%20Integer) | `Math` |
+| 009 | [Palindrome Number](https://github.com/doocs/leetcode/tree/master/solution/009.Palindrome%20Number) | `Math` |
 | 013 | [Roman to Integer](https://github.com/doocs/leetcode/tree/master/solution/013.Roman%20to%20Integer) | `Math`, `String` |
 | 014 | [Longest Common Prefix](https://github.com/doocs/leetcode/tree/master/solution/014.Longest%20Common%20Prefix) | `String` |
 | 020 | [Valid Parentheses](https://github.com/doocs/leetcode/tree/master/solution/020.Valid%20Parentheses) | `String`, `Stack` |
 | 021 | [Merge Two Sorted Lists](https://github.com/doocs/leetcode/tree/master/solution/021.Merge%20Two%20Sorted%20Lists) | `Linked List` |
+| 028 | [Implement strStr()](https://github.com/doocs/leetcode/tree/master/solution/028.Implement%20strStr()) | `Two Pointers`, `String` |
+| 035 | [Search Insert Position](https://github.com/doocs/leetcode/tree/master/solution/035.Search%20Insert%20Position) | `Array`, `Binary Search` |
 | 053 | [Maximum Subarray](https://github.com/doocs/leetcode/tree/master/solution/053.Maximum%20Subarray) | `Array`, `Divide and Conquer`, `Dynamic Programming` |
 | 070 | [Climbing Stairs](https://github.com/doocs/leetcode/tree/master/solution/070.Climbing%20Stairs) | `Dynamic Programming` |
 | 083 | [Remove Duplicates from Sorted List](https://github.com/doocs/leetcode/tree/master/solution/083.Remove%20Duplicates%20from%20Sorted%20List) | `Linked List` |
 | 136 | [Single Number](https://github.com/doocs/leetcode/tree/master/solution/136.Single%20Number) | `Hash Table`, `Bit Manipulation` |
+| 141 | [Linked List Cycle](https://github.com/doocs/leetcode/tree/master/solution/141.Linked%20List%20Cycle) | `Linked List`, `Two Pointers` |
 | 189 | [Rotate Array](https://github.com/doocs/leetcode/tree/master/solution/189.Rotate%20Array) | `Array` |
 | 198 | [House Robber](https://github.com/doocs/leetcode/tree/master/solution/198.House%20Robber) | `Dynamic Programming` |
 | 203 | [Remove Linked List Elements](https://github.com/doocs/leetcode/tree/master/solution/203.Remove%20Linked%20List%20Elements) | `Linked List` |
 | 231 | [Power of Two](https://github.com/doocs/leetcode/tree/master/solution/231.Power%20of%20Two) | `Math`, `Bit Manipulation` |
+| 234 | [Palindrome Linked List](https://github.com/doocs/leetcode/tree/master/solution/234.Palindrome%20Linked%20List) | `Linked List`, `Two Pointers` |
 | 235 | [Lowest Common Ancestor of a Binary Search Tree](https://github.com/doocs/leetcode/tree/master/solution/235.Lowest%20Common%20Ancestor%20of%20a%20Binary%20Search%20Tree) | `Tree` |
 | 237 | [Delete Node in a Linked List](https://github.com/doocs/leetcode/tree/master/solution/237.Delete%20Node%20in%20a%20Linked%20List) | `Linked List` |
 | 344 | [Reverse String](https://github.com/doocs/leetcode/tree/master/solution/344.Reverse%20String) | `Two Pointers`, `String` |
+| 581 | [Shortest Unsorted Continuous Subarray](https://github.com/doocs/leetcode/tree/master/solution/581.Shortest%20Unsorted%20Continuous%20Subarray) | `Array` |
+| 695 | [Max Area of Island](https://github.com/doocs/leetcode/tree/master/solution/695.Max%20Area%20of%20Island) | `Array`, `Depth-first Search` |
 | 703 | [Kth Largest Element in a Stream](https://github.com/doocs/leetcode/tree/master/solution/703.Kth%20Largest%20Element%20in%20a%20Stream) | `Heap` |
+| 707 | [Design Linked List](https://github.com/doocs/leetcode/tree/master/solution/707.Design%20Linked%20List) | `Linked List`, `Design` |
 | 876 | [Middle of the Linked List](https://github.com/doocs/leetcode/tree/master/solution/876.Middle%20of%20the%20Linked%20List) | `Linked List` |
 
 
@@ -45,12 +53,18 @@ Complete solutions to Leetcode problems, updated daily.
 | # | Title | Tags |
 |---|---|---|
 | 002 | [Add Two Numbers](https://github.com/doocs/leetcode/tree/master/solution/002.Add%20Two%20Numbers) | `Linked List`, `Math` |
+| 003 | [Longest Substring Without Repeating Characters](https://github.com/doocs/leetcode/tree/master/solution/003.Longest%20Substring%20Without%20Repeating%20Characters) | `Hash Table`, `Two Pointers`, `String` |
+| 005 | [Longest Palindromic Substring](https://github.com/doocs/leetcode/tree/master/solution/005.Longest%20Palindromic%20Substring) | `String`, `Dynamic Programming` |
 | 015 | [3Sum](https://github.com/doocs/leetcode/tree/master/solution/015.3Sum) | `Array`, `Two Pointers` |
+| 018 | [4Sum](https://github.com/doocs/leetcode/tree/master/solution/018.4Sum) | `Array`, `Hash Table`, `Two Pointers` |
 | 019 | [Remove Nth Node From End of List](https://github.com/doocs/leetcode/tree/master/solution/019.Remove%20Nth%20Node%20From%20End%20of%20List) | `Linked List`, `Two Pointers` |
 | 024 | [Swap Nodes in Pairs](https://github.com/doocs/leetcode/tree/master/solution/024.Swap%20Nodes%20in%20Pairs) | `Linked List` |
 | 031 | [Next Permutation](https://github.com/doocs/leetcode/tree/master/solution/031.Next%20Permutation) | `Array` |
 | 046 | [Permutations](https://github.com/doocs/leetcode/tree/master/solution/046.Permutations) | `Backtracking` |
 | 047 | [Permutations II](https://github.com/doocs/leetcode/tree/master/solution/047.Permutations%20II) | `Backtracking` |
+| 054 | [Spiral Matrix](https://github.com/doocs/leetcode/tree/master/solution/054.Spiral%20Matrix) | `Array` |
+| 059 | [Spiral Matrix II](https://github.com/doocs/leetcode/tree/master/solution/059.Spiral%20Matrix%20II) | `Array` |
+| 061 | [Rotate List](https://github.com/doocs/leetcode/tree/master/solution/061.Rotate%20List) | `Linked List`, `Two Pointers` |
 | 062 | [Unique Paths](https://github.com/doocs/leetcode/tree/master/solution/062.Unique%20Paths) | `Array`, `Dynamic Programming` |
 | 063 | [Unique Paths II](https://github.com/doocs/leetcode/tree/master/solution/063.Unique%20Paths%20II) | `Array`, `Dynamic Programming` |
 | 075 | [Sort Colors](https://github.com/doocs/leetcode/tree/master/solution/075.Sort%20Colors) | `Array`, `Two Pointers`, `Sort` |
@@ -62,30 +76,38 @@ Complete solutions to Leetcode problems, updated daily.
 | 127 | [Word Ladder](https://github.com/doocs/leetcode/tree/master/solution/127.Word%20Ladder) | `Breadth-first Search` |
 | 130 | [Surrounded Regions](https://github.com/doocs/leetcode/tree/master/solution/130.Surrounded%20Regions) | `Depth-first Search`, `Breadth-first Search`, `Union Find` |
 | 137 | [Single Number II](https://github.com/doocs/leetcode/tree/master/solution/137.Single%20Number%20II) | `Bit Manipulation` |
+| 142 | [Linked List Cycle II](https://github.com/doocs/leetcode/tree/master/solution/142.Linked%20List%20Cycle%20II) | `Linked List`, `Two Pointers` |
+| 143| [Reorder List](https://github.com/doocs/leetcode/tree/master/solution/143.Reorder%20List) | `Linked List` |
 | 144 | [Binary Tree Preorder Traversal](https://github.com/doocs/leetcode/tree/master/solution/144.Binary%20Tree%20Preorder%20Traversal) | `Stack`, `Tree` |
 | 150 | [Evaluate Reverse Polish Notation](https://github.com/doocs/leetcode/tree/master/solution/150.Evaluate%20Reverse%20Polish%20Notation) | `Stack` |
 | 153 | [Find Minimum in Rotated Sorted Array](https://github.com/doocs/leetcode/tree/master/solution/153.Find%20Minimum%20in%20Rotated%20Sorted%20Array) | `Array`, `Binary Search` |
+| 328 | [Odd Even Linked List](https://github.com/doocs/leetcode/tree/master/solution/328.Odd%20Even%20Linked%20List) | `Linked List` |
 
 
 ### Hard
 
 | # | Title | Tags |
 |---|---|---|
+| 004 | [Median of Two Sorted Arrays](https://github.com/doocs/leetcode/tree/master/solution/004.Median%20of%20Two%20Sorted%20Arrays) | `Array`, `Binary Search`, `Divide and Conquer` |
 | 023 | [Merge k Sorted Lists](https://github.com/doocs/leetcode/tree/master/solution/023.Merge%20k%20Sorted%20Lists) | `Linked List`, `Divide and Conquer`, `Heap` |
 | 032 | [Longest Valid Parentheses](https://github.com/doocs/leetcode/tree/master/solution/032.Longest%20Valid%20Parentheses) | `String`, `Dynamic Programming` |
 | 084 | [Largest Rectangle in Histogram](https://github.com/doocs/leetcode/tree/master/solution/084.Largest%20Rectangle%20in%20Histogram) | `Array`, `Stack` |
 | 145 | [Binary Tree Postorder Traversal](https://github.com/doocs/leetcode/tree/master/solution/145.Binary%20Tree%20Postorder%20Traversal) | `Stack`, `Tree` |
 | 295 | [Find Median from Data Stream](https://github.com/doocs/leetcode/tree/master/solution/295.Find%20Median%20from%20Data%20Stream) | `Heap`, `Design` |
 
+
 ## Contributions
-I'm looking for long-term contributors/partners to this repo! Send me PRs if you're interested! See the following:
+I'm looking for long-term contributors/partners to this repo! Send me [PRs](https://github.com/doocs/leetcode/pulls) if you're interested! See the following:
 - Fork this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device.
 - Submit a pull request with your changes!
 
 ## Contributors
 
+" If you want to go fast, go alone. If you want to go far, go together. And that's the spirit of [teamwork](https://github.com/doocs/leetcode/graphs/contributors) ".
+
 <!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
-| <center> [<img src="https://avatars3.githubusercontent.com/u/21008209?v=4" width="100px;"/><br /><sub><b>yanglbme</b></sub>](https://github.com/yanglbme)<br />[💻](https://github.com/doocs/leetcode/commits?author=yanglbme "Code") </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/23625436?v=4" width="100px;"/><br /><sub><b>chakyam</b></sub>](https://github.com/chakyam)<br />[💻](https://github.com/doocs/leetcode/commits?author=chakyam "Code") </center> | 
-|---|---|
+| <center> [<img src="https://avatars3.githubusercontent.com/u/21008209?v=4" width="80px;"/>](https://github.com/yanglbme) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/23625436?v=4" width="80px;"/>](https://github.com/chakyam) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/10081554?v=4" width="80px;"/>](https://github.com/zhkmxx9302013) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/40383345?v=4" width="80px;"/>](https://github.com/MarkKuang1991) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/12371194?v=4" width="80px;"/>](https://github.com/fonxian) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/25222367?v=4" width="80px;"/>](https://github.com/zhanary) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/42396616?v=4" width="80px;"/>](https://github.com/ZhouTingZhaobiu) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/31923541?v=4" width="80px;"/>](https://github.com/zouwx2cs) </center> |
+|---|---|---|---|---|---|---|---|
+| <center> [<img src="https://avatars3.githubusercontent.com/u/20679510?v=4" width="80px;"/>](https://github.com/Mrzhudky) </center> |
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->

solution/001.Two Sum/Solution.cpp

@@ -0,0 +1,24 @@
+class Solution {
+public:
+    vector<int> twoSum(vector<int>& nums, int target) 
+    {
+        vector<int> res ;
+        unordered_map<int, int> hash ;
+        
+        for (int i = 0; i < nums.size(); ++i)
+        {
+            int aim = target - nums[i] ;
+            int local = hash[aim] ; 
+            if (local != NULL)
+            {
+                res.push_back(local-1) ;
+                res.push_back(i) ;
+                return res ;
+            }
+            else
+                hash[nums[i]] = i+1 ;
+        }
+
+        return res ;
+    }
+};

solution/001.Two Sum/Solution.go

@@ -0,0 +1,12 @@
+func twoSum(nums []int, target int) []int {
+	var numsMap map[int]int
+	numsMap = make(map[int]int)
+	for i := 0; i < len(nums); i++ {
+		if _, ok := numsMap[target-nums[i]]; ok {
+
+			return []int{numsMap[target-nums[i]], i}
+		}
+		numsMap[nums[i]] = i
+	}
+	return nil
+}

solution/001.Two Sum/Solution.rb

@@ -0,0 +1,11 @@
+# @param {Integer[]} nums
+# @param {Integer} target
+# @return {Integer[]}
+def two_sum(nums, target)
+  nums.each_with_index do |x, idx|
+    if nums.include? target - x
+      return [idx, nums.index(target - x)] if nums.index(target - x) != idx
+    end
+    next
+  end
+end

solution/001.Two Sum/Solution.scala

@@ -0,0 +1,15 @@
+import scala.collection.mutable
+
+object Solution {
+  def twoSum(nums: Array[Int], target: Int): Array[Int] = {
+    var map = new mutable.HashMap[Int, Int]()
+    for (i <- 0 to nums.length) {
+      if (map.contains(target - nums(i))) {
+        return Array(map(target - nums(i)), i)
+      } else {
+        map += (nums(i) -> i)
+      }
+    }
+    Array(0, 0)
+  }
+}

solution/001.Two Sum/Solution2.py

@@ -0,0 +1,10 @@
+#time 32ms
+class Solution(object):
+    def twoSum(self, nums, target):
+        buff = {}
+        for i in range(len(nums)):
+            if nums[i] in buff:     #如果这个数在字典里，证明之前有数可以和他匹配
+                return buff[nums[i]],i   #返回之前留信息的数的编号，和当前这个数的编号
+            else: 
+                buff[target - nums[i]] = i   #这个数字不在字典里，那么就存一下他需要匹配的数，并记录编号
+

solution/002.Add Two Numbers/Solution.rb

@@ -0,0 +1,37 @@
+# Definition for singly-linked list.
+# class ListNode
+#     attr_accessor :val, :next
+#     def initialize(val)
+#         @val = val
+#         @next = nil
+#     end
+# end
+
+# @param {ListNode} l1
+# @param {ListNode} l2
+# @return {ListNode}
+
+def add_two_numbers(l1, l2)
+  return l2 if l1 == nil
+  return l1 if l2 == nil
+  cur_val = l1.val + l2.val
+  l3 = ListNode.new(cur_val % 10)
+  add = cur_val >= 10 ? 1 : 0
+  tmp = l3
+
+  l1 = l1.next
+  l2 = l2.next
+  while !l1.nil? || !l2.nil? || add > 0
+    cur_val = add
+    cur_val += l1.nil? ? 0 : l1.val
+    cur_val += l2.nil? ? 0 : l2.val
+    tmp.next = ListNode.new(cur_val % 10)
+    tmp = tmp.next
+    add = cur_val >= 10 ? 1 : 0
+
+    l1 = l1.nil? ? l1 : l1.next
+    l2 = l2.nil? ? l2 : l2.next
+  end
+
+  l3
+end

solution/003.Longest Substring Without Repeating Characters/README.md

@@ -0,0 +1,57 @@
+## 无重复字符的最长子串
+### 题目描述
+
+给定一个字符串，找出不含有重复字符的**最长子串**的长度。
+
+**示例 1:**
+```
+输入: "abcabcbb"
+输出: 3 
+解释: 无重复字符的最长子串是 "abc"，其长度为 3。
+```
+
+**示例 2:**
+```
+输入: "bbbbb"
+输出: 1
+解释: 无重复字符的最长子串是 "b"，其长度为 1。
+```
+
+**示例 3:**
+```
+输入: "pwwkew"
+输出: 3
+解释: 无重复字符的最长子串是 "wke"，其长度为 3。
+     请注意，答案必须是一个子串，"pwke" 是一个子序列 而不是子串。
+```
+
+### 解法
+利用指针 `p`, `q`，初始指向字符串开头。遍历字符串，`q` 向右移动，若指向的字符在 map 中，说明出现了重复字符，此时，`p` 要在出现**重复字符的下一个位置** `map.get(chars[q]) + 1` 和**当前位置** `p` 之间取较大值，防止 `p` 指针回溯。循环的过程中，要将 chars[q] 及对应位置放入 map 中，也需要不断计算出`max` 与 `q - p + 1` 的较大值，赋给 `max`。最后输出 `max` 即可。
+
+```java
+class Solution {
+    public int lengthOfLongestSubstring(String s) {
+        if (s == null || s.length() == 0) {
+            return 0;
+        }
+        char[] chars = s.toCharArray();
+        int len = chars.length;
+        int p = 0, q = 0;
+        int max = 0;
+        Map<Character, Integer> map = new HashMap<>();
+        while (q < len) {
+            if (map.containsKey(chars[q])) {
+                // 防止p指针回溯，导致计算到重复字符的长度
+                // eg. abba,当p指向最右的a时，若简单把p赋为map.get(chars[q] + 1)，则出现指针回溯
+                p = Math.max(p, map.get(chars[q]) + 1);
+            }
+            map.put(chars[q], q);
+            max = Math.max(max, q - p + 1);
+            ++q;
+        }
+        
+        return max;
+    }
+}
+```
+

solution/003.Longest Substring Without Repeating Characters/Solution.java

@@ -0,0 +1,23 @@
+class Solution {
+    public int lengthOfLongestSubstring(String s) {
+        if (s == null || s.length() == 0) {
+            return 0;
+        }
+        char[] chars = s.toCharArray();
+        int len = chars.length;
+        int p = 0, q = 0;
+        int max = 0;
+        Map<Character, Integer> map = new HashMap<>();
+        while (q < len) {
+            if (map.containsKey(chars[q])) {
+                // 防止p指针回溯，导致计算到重复字符的长度
+                p = Math.max(p, map.get(chars[q]) + 1);
+            }
+            map.put(chars[q], q);
+            max = Math.max(max, q - p + 1);
+            ++q;
+        }
+
+        return max;
+    }
+}