1、题目
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
2、代码实现
public class Solution { public boolean canConstruct(String ransomNote, String magazine) { if (magazine == null) return false; if (ransomNote == null) return false; if (ransomNote.length() == 0 && magazine.length() == 0) return true; List<Character> list = new ArrayList<Character>(); for (char c : magazine.toCharArray()) { list.add(Character.valueOf(c)); } if (ransomNote.length() == magazine.length()) { for (int i = 0; i < ransomNote.length(); i++) { if (!list.remove(Character.valueOf(ransomNote.charAt(i)))) { return false; } } return true; } else { for (int i = 0; i < ransomNote.length(); i++) { if (!list.remove(Character.valueOf(ransomNote.charAt(i)))) { return false; } } if (list.size() > 0) { return true; } } return false; } }
