[leetcode] 383. Ransom Note 解题报告

来源：互联网发布：知其雄编辑：程序博客网时间：2024/05/08 03:06

题目链接: https://leetcode.com/problems/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") -> falsecanConstruct("aa", "ab") -> falsecanConstruct("aa", "aab") -> true

思路: 一个hash表即可

代码如下:

class Solution {public:    bool canConstruct(string ransomNote, string magazine) {        unordered_map<char, int> hash;        for(auto ch: magazine) hash[ch]++;        for(auto ch: ransomNote)            if(--hash[ch]<0) return false;        return true;    }};

0 0