String class issue

1, if the title explicitly contain only letters, consider a hash table

String solution to a problem can refer to: http: //3ms.huawei.com/km/blogs/details/7606175

LeetCode Frequently Asked Questions:

1, the arrangement of the string
https://leetcode-cn.com/problems/permutation-in-string/

2, spell words
https://leetcode-cn.com/problems/find-words-that-can-be-formed-by-characters/

3,  the string multiplied

https://leetcode-cn.com/problems/multiply-strings/

5, the reconstructed string
https://leetcode-cn.com/problems/reorganize-string/

567. The arrangement of strings
https://leetcode-cn.com/problems/permutation-in-string/
1160. The spelling of the word
https://leetcode-cn.com/problems/find-words-that-can-be- formed-by-characters /

String:
43. string multiplied
https://leetcode-cn.com/problems/multiply-strings/
767. reconstructed string
https://leetcode-cn.com/problems/reorganize-string/
1268. Search recommended system
https://leetcode-cn.com/problems/search-suggestions-system/