典型的近似子串問(wèn)題！

Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false.

Each letter in the magazine string can only be used once in your ransom note.

Note: You may assume that both strings contain only lowercase letters.

canConstruct(“a”, “b”) -> false canConstruct(“aa”, “ab”) -> false canConstruct(“aa”, “aab”) -> true

給你左右兩個(gè)字符串，判斷左側(cè)子串是否可以由右側(cè)字符串中抽取部分字符得到（右側(cè)字符串每個(gè)字母僅可用一次），全都是小寫字母。

思路：建立數(shù)組存儲(chǔ)每個(gè)字母出現(xiàn)的次數(shù)