档案日期2018的18

题目描述：

LeetCode 828. Unique Letter String

A character is unique in string S if it occurs exactly once in it.

For example, in string S = "LETTER", the only unique characters are "L" and "R".

Let's define UNIQ(S) as the ...

题目描述：

LeetCode 829. Consecutive Numbers Sum

Given a positive integer N, how many ways can we write it as a sum of consecutive positive integers?

Example 1:

Input: 5
Output: 2
Explanation: 5 = 5 = 2 + 3

Example 2:

Input: 9
Output ...

题目描述：

LeetCode 831. Masking Personal Information

We are given a personal information string S, which may represent either an email address or a phone number.

We would like to mask this personal information according to the following rules:

1. Email address:

We define a  ...

题目描述：

LeetCode 830. Positions of Large Groups

In a string S of lowercase letters, these letters form consecutive groups of the same character.

For example, a string like S = "abbxxxxzyy" has the groups "a", "bb", "xxxx", "z" and "yy".

Call ...