Merge branch 'master' of https://github.com/azl397985856/leetcode

Author: luzhipeng

problems/20.validParentheses.md

@@ -70,7 +70,9 @@ Output: true
 > 入： push  出 shift 就是队列
 ## 代码
 
+* 语言支持：JS，Python
 
+Javascript Code:
 ```js
 /*
  * @lc app=leetcode id=20 lang=javascript
@@ -163,6 +165,30 @@ var isValid = function(s) {
     return valid;
 };
 ```
+Python Code:
+```
+    class Solution:
+        def isValid(self,s):
+          stack = []
+          map = {
+            "{":"}",
+            "[":"]",
+            "(":")"
+          }
+          for x in s:
+            if x in map:
+              stack.append(map[x])
+            else:
+              if len(stack)!=0:
+                top_element = stack.pop()
+                if x != top_element:
+                  return False
+                else:
+                  continue
+              else:
+                return False
+          return len(stack) == 0
+```
 
 ## 扩展
-如果让你检查XML标签是否闭合如何检查， 更进一步如果要你实现一个简单的XML的解析器，应该怎么实现？
+如果让你检查XML标签是否闭合如何检查， 更进一步如果要你实现一个简单的XML的解析器，应该怎么实现？

problems/3.longestSubstringWithoutRepeatingCharacters.md

@@ -1,3 +1,6 @@
+## 题目地址
+https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
+
 ## 题目描述
 Given a string, find the length of the longest substring without repeating characters.