Merge branch 'master' into master

Author: KongJHong

README.md

@@ -130,6 +130,6 @@ I'm looking for long-term contributors/partners to this repo! Send me [PRs](http
 | <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> | <center> [<img src="https://avatars3.githubusercontent.com/u/44309823?v=4" width="80px;"/>](https://github.com/KongJHong) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/18181519?v=4" width="80px;"/>](https://github.com/limbowandering) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/37685012?v=4" width="80px;"/>](https://github.com/jxdeng3989) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/44314231?v=4" width="80px;"/>](https://github.com/igayhub) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/30177307?v=4" width="80px;"/>](https://github.com/MCN1998) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/5793058?v=4" width="80px;"/>](https://github.com/Fairyhead) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/24841082?v=4" width="80px;"/>](https://github.com/zhng1456) </center> |
-| <center> [<img src="https://avatars3.githubusercontent.com/u/32598987?v=4" width="80px;"/>](https://github.com/xiapengchng) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/37660444?v=4" width="80px;"/>](https://github.com/Mcnwork2018) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/22535595?v=4" width="80px;"/>](https://github.com/bluesword12350) </center> |
+| <center> [<img src="https://avatars3.githubusercontent.com/u/32598987?v=4" width="80px;"/>](https://github.com/xiapengchng) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/37660444?v=4" width="80px;"/>](https://github.com/Mcnwork2018) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/22535595?v=4" width="80px;"/>](https://github.com/bluesword12350) </center> | <center> [<img src="https://avatars3.githubusercontent.com/u/39827514?v=4" width="80px;"/>](https://github.com/ashwek) </center> |
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->

solution/009.Palindrome Number/Solution.py

@@ -0,0 +1,10 @@
+class Solution:
+    def isPalindrome(self, num):
+        """
+        :type num: int
+        :rtype: bool
+        """
+        if num < 0:
+            return False
+        
+        return str(num) == str(num)[::-1]

solution/014.Longest Common Prefix/Solution.cpp

@@ -0,0 +1,37 @@
+static int x=[](){
+    std::ios::sync_with_stdio(false);
+    cin.tie(NULL);
+    return 0;
+}();
+string Compare(string s1,string s2)
+{
+    if(s1.size()==0||s2.size()==0)
+        return "";
+    int num=s1.size()<s2.size()?s1.size():s2.size();
+    string s;
+    for(int i=0;i<num;i++)
+    {
+        if(s1[i]==s2[i])
+        {
+            s.push_back(s1[i]);
+        }
+        else
+            break;
+        
+    }
+    return s;
+}
+class Solution {
+public:
+    string longestCommonPrefix(vector<string>& strs) {
+        if(strs.size()==0)
+            return "";
+        string prefix=strs[0];
+        for(int i=1;i<strs.size();i++)
+        {
+            prefix=Compare(prefix,strs[i]);
+        }
+        return prefix;
+        
+    }
+};

solution/016. 3Sum Closest/Solution.java

@@ -0,0 +1,17 @@
+class Solution {
+    public int threeSumClosest(int[] nums, int target) {
+        int result = nums[0]+nums[1]+nums[2];
+        Arrays.sort(nums);
+        for(int i = 0;i<nums.length-2;i++){
+            int start = i+1,end=nums.length-1;
+            while(start<end){
+                int cache = nums[i]+nums[start]+nums[end];
+                if(Math.abs(cache-target)<Math.abs(result-target)) result = cache;
+                if(cache < target ) start++;
+                else if(cache > target) end--;
+                else return result;
+            }
+        }
+        return result;
+    }
+}

solution/017. Letter Combinations of a Phone Number/Solution.java

@@ -0,0 +1,30 @@
+class Solution {
+    public List<String> letterCombinations(String digits) {
+        char[] cs = digits.toCharArray();
+        List<String> result = new ArrayList<>();
+        for (char a : cs) {
+            char[] charArray;
+            switch (a) {
+                case '2': charArray = new char[]{'a','b','c'}; break;
+                case '3': charArray = new char[]{'d','e','f'}; break;
+                case '4': charArray = new char[]{'g','h','i'}; break;
+                case '5': charArray = new char[]{'j','k','l'}; break;
+                case '6': charArray = new char[]{'m','n','o'}; break;
+                case '7': charArray = new char[]{'p','q','r','s'}; break;
+                case '8': charArray = new char[]{'t','u','v'}; break;
+                case '9': charArray = new char[]{'w','x','y','z'}; break;
+                default: return null;
+            }
+            if (result.size() == 0) {
+                for (char aCharArray : charArray) result.add(String.valueOf(aCharArray));
+            } else {
+                List<String> cache = new ArrayList<>();
+                for (String string : result) {
+                    for (char aCharArray : charArray) cache.add(string + aCharArray);
+                }
+                result = cache;
+            }
+        }
+        return result;
+    }
+}

solution/021.Merge Two Sorted Lists/Solution.cpp

@@ -0,0 +1,37 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
+        ListNode *a1=new ListNode(0);
+        ListNode *head=a1;
+        while(l1!=NULL&&l2!=NULL)
+        {
+            if(l1->val<l2->val)
+            {
+                a1->next=l1;
+                l1=l1->next;
+                a1=a1->next;
+            }
+            else
+            {
+                a1->next=l2;
+                l2=l2->next;
+                a1=a1->next;
+            }
+        }
+        if(l1==NULL)
+            a1->next=l2;
+        if(l2==NULL)
+            a1->next=l1;
+        return head->next;
+        
+        
+    }
+};

solution/053.Maximum Subarray/Solution.js

@@ -0,0 +1,9 @@
+const maxSubArray = function(nums){
+  if(nums.length === 0) return 0;
+  let ans = nums[0], tmp = nums[0];
+  for(let i = 1; i < nums.length; i++){
+    tmp = Math.max(tmp+nums[i], nums[i]);
+    ans = Math.max(ans,tmp);
+  }
+  return ans;
+}

solution/062.Unique Paths/Solution.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    int uniquePaths(int m, int n) {
+        if(m<=0||n<=0)
+            return 0;
+        if(m==1||n==1)
+            return 1;
+        int arr[m][n]={0};
+        arr[0][0]=1;
+        for(int i=1;i<m;i++)
+            arr[i][0]=1;
+        for(int j=1;j<n;j++)
+            arr[0][j]=1;
+        for(int i=1;i<m;i++)
+            for(int j=1;j<n;j++)
+            {
+                arr[i][j]=arr[i-1][j]+arr[i][j-1];
+            }
+        return arr[m-1][n-1];
+    }
+};

solution/070.Climbing Stairs/Solution.cpp

@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int climbStairs(int n) {
+        
+        if(n==1)
+            return 1;
+        if(n==2)
+            return 2;
+        int arr[n]={0};
+        arr[0]=1;
+        arr[1]=2;
+        for(int i=2;i<n;i++)
+            arr[i]=arr[i-1]+arr[i-2];
+        return arr[n-1];
+        
+    }
+};

solution/070.Climbing Stairs/Solution.js

@@ -0,0 +1,9 @@
+const climbStairs = function(n){
+  let arr = [];
+  arr[0] = 1;
+  arr[1] = 1;
+  for(let i = 2; i <= n; i++){
+    arr[i] = arr[i-1]+arr[i-2];
+  }
+  return arr[n];
+};

solution/075.Sort Colors/Solution2.py

@@ -0,0 +1,15 @@
+class Solution2:
+    def sortColors(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: void Do not return anything, modify nums in-place instead.
+        """
+        Count = [nums.count(color) for color in range(3)]
+
+        color = i = 0
+
+        while i < len(nums):
+            for j in range(Count[color]):
+                nums[i] = color
+                i += 1
+            color += 1

solution/084.Largest Rectangle in Histogram/README.md

@@ -19,41 +19,16 @@
 输出: 10
 ```
 
-### 解法1
+### 解法
+#### 思路一
 从前往后遍历 heightss[0...n]：
 
 - 若 heightss[i] > heightss[i - 1]，则将 i 压入栈中；
 - 若 heightss[i] <= heightss[i - 1]，则依次弹出栈，计算栈中能得到的最大矩形面积。
 
 注意，压入栈中的是柱子的索引，而非柱子的高度。（通过索引可以获得高度、距离差）
 
-### 解法2:构建升序栈
 
-[见原文(方法二)](https://blog.csdn.net/jingsuwen1/article/details/51577983)
-
-其实是对第一种解法的一种补充解释，同样是构建升序栈
-
-数学模型分析：
->假设题目中有升序水柱 {1,2,3,4,5,6}，构建成栈内元素stack = {1,2,3,4,5,6}
->
->假设第7个入栈元素（水柱）值为4时，栈顶元素6出栈，因为是首位出栈的元素，count = 1。表示高度为6的柱最大宽度是1，最大面积是ans = 6 * 1；
->
->stack={1,2,3,4,5};想入栈的元素还是刚才那个4,栈顶元素：5>4，所以5要出栈，因为是连续出栈的第二个元素，所以count++。表示高度为5的柱最大宽度是2，最大面积是ans = max(ans,5 * 2) = 10;
->
->stack={1,2,3,4};想入栈的还是那个4，现在栈顶元素:4=4了，直接入栈:stack={1,2,3,4,4}
->
->因为count=2,柱子数量应该和heights[i]下标i相同来补位,所以要进去两个数，即要补count个heights[i]
->
->stack={1,2,3,4,4,4,4}
-
-1. 初始化一个空栈，下标`i = 0`，数组首位元素入栈，下标`i++`，出栈个数`count = 0`
-2. 当heights[i]>=stack.top()，heights[i]入栈`i++,count =0`；否则，栈顶出栈，设置计数位count++,统计以栈顶元素出栈个数,`ans = max(ans,stack.top()*count)`,循环这一步操作
-3. 若count>0,补全栈内元素；count=0不处理
-4. 循环结束后计算升序栈以各元素为高的水柱面积
-
-
-------------------------------
-### JAVA(解法1)
 
 ```java
 class Solution {
@@ -94,7 +69,9 @@ class Solution {
 }
 ```
 
-### CPP(解法2)
+
+
+**C++版实现：**
 
 ```CPP
 class Solution {

solution/121.Best Time to Buy and Sell Stock/Solution.js

@@ -0,0 +1,13 @@
+const maxProfit1 = function(prices){
+  let min = prices[0];
+  let profit = 0;
+  for(let i = 0; i < prices.length; i++){
+    if(prices[i] < min){
+      min = prices[i];
+    }
+    if(profit < (prices[i] - min)){
+      profit = prices[i] - min;
+    }
+  }
+  return profit;
+}

solution/122.Best Time to Buy and Sell Stock II/Solution.js

@@ -0,0 +1,9 @@
+const maxProfit2 = function(prices){
+  let profit = 0;
+  for(let i = 1; i < prices.length; i++){
+    if(prices[i]-prices[i-1] > 0){
+      profit+=prices[i]-prices[i-1];
+    }
+  }
+  return profit;
+}