LeetCode 383. Ransom Note
https://leetcode.com/problems/ransom-note/ 原题地址
题目描述
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
解法：
class Solution { public: bool canConstruct(string ransomNote, string magazine) { vector<int> num(26); for(int i = 0; i < magazine.size(); i++)## 遍历 magazine，巧妙利用数组下标 num[magazine[i] - ‘a‘]++; for(int i = 0; i < ransomNote.size(); i++){ num[ransomNote[i] - ‘a‘]--; if(num[ransomNote[i]- ‘a‘] < 0)## 出现负数则返回false return false; } return true; } };
原文：https://www.cnblogs.com/dingxi/p/11523517.html