Q:
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.
You may assume that both strings contain only lowercase letters.
canConstruct("a", "b") -> false canConstruct("aa", "ab") -> false canConstruct("aa", "aab") -> true
A:
public class Solution { public boolean canConstruct(String ransomNote, String magazine) { Map<Character, Integer> map = new HashMap<>(); for(char ch : magazine.toCharArray()){ map.put(ch, map.containsKey(ch)?map.get(ch)+1:1 ); } for(char ch : ransomNote.toCharArray()){ if(!map.containsKey(ch)){ return false; } map.put(ch, map.get(ch)-1); if(map.get(ch)==0) map.remove(ch); } return true; } }
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