383. Ransom Note

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

(1) Java

(2) Python

class Solution:
    def canConstruct(self, ransomNote, magazine):
        """
        :type ransomNote: str
        :type magazine: str
        :rtype: bool
        """
        chars = [0]*26
        for c in magazine:
            idx = ord(c) - ord('a')
            chars[idx] += 1
        for v in ransomNote:
            idx = ord(v) -  ord('a')
            chars[idx] -= 1
            if chars[idx] < 0:
                return False
        return True

(3) Scala