2255. Count Prefixes of a Given String
You are given a string array words and a string s, where words[i] and s comprise only of lowercase English letters.
Return the number of strings in words that are a prefix of s.
A prefix of a string is a substring that occurs at the beginning of the string. A substring is a contiguous sequence of characters within a string.
Write an API that generates fancy sequences using the append, addAll, and multAll operations.
Implement the Fancy class:
- Fancy() Initializes the object with an empty sequence.
- void append(val) Appends an integer val to the end of the sequence.
- void addAll(inc) Increments all existing values in the sequence by an integer inc.
- void multAll(m) Multiplies all existing values in the sequence by an integer m.
- int getIndex(idx) Gets the current value at index idx (0-indexed) of the sequence modulo 109 + 7. If the index is greater or equal than the length of the sequence, return -1.
There is only one character ‘A’ on the screen of a notepad. You can perform one of two operations on this notepad for each step:
- Copy All: You can copy all the characters present on the screen (a partial copy is not allowed).
- Paste: You can paste the characters which are copied last time.
Given an integer n, return the minimum number of operations to get the character ‘A’ exactly n times on the screen.