lstring

Overview ¶

https://leetcode.com/problems/add-binary/#/description

Given two binary strings, return their sum (also a binary string).

For example, a = "11" b = "1" Return "100".

https://leetcode.com/problems/valid-parentheses/#/description

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.

https://leetcode.com/problems/judge-route-circle/description/

Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the original place.

The move sequence is represented by a string. And each move is represent by a character. The valid robot moves are R (Right), L (Left), U (Up) and D (down). The output should be true or false representing whether the robot makes a circle.

Example 1:

Input: "UD"
Output: true

Example 2:

   Input: "LL"
   Output: false

https://leetcode.com/problems/longest-substring-without-repeating-characters/#/description

Given a string, find the length of the longest substring without repeating characters.

Examples:

Given "abcabcbb", the answer is "abc", which the length is 3.

Given "bbbbb", the answer is "b", with the length of 1.

Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequence and not a substring.

https://leetcode.com/problems/longest-common-prefix/#/description

Write a function to find the longest common prefix string amongst an array of strings.

https://leetcode.com/problems/reverse-vowels-of-a-string/#/description

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1: Given s = "hello", return "holle".

Example 2: Given s = "leetcode", return "leotcede".

Note: The vowels does not include the letter "y".