[LeetCode] 383. Ransom Note

轉自LeetCode

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

<Solution>
想法如下

• 使用一個 hash map 來記錄 magazine 出現的字元，以及次數

• 檢查在 ransom note 裡面的字元，是不是存在 hash map 中，以及沒有超過次數

code 如下

C++

Java