242 - Valid Anagram

Valid Anagram

Given two strings s and t, write a function to determine if t is an anagram of s.

For example,
s = "anagram", t = "nagaram", return true.
s = "rat", t = "car", return false.

Note:
You may assume the string contains only lowercase alphabets.

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Hash Table Sort

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(M) Anagrams

 

用个辅助数组统计，O(n)，12ms。（当然也可以用hash表）

试了一下用sort，80ms，不划算。

class Solution {
public:
    bool isAnagram(string s, string t) {
        int ls=s.length(), lt=t.length();
       
        if(ls!=lt)
            return false;
       
        if(s==t)
            return true;
           
        int check[26]={0};
       
        for(int ii=ls-1; ii>=0; ii--)
            check[s[ii]-'a']++;
       
        for(int ii=lt-1; ii>=0; ii--)
            check[t[ii]-'a']--;

        for(int ii=25; ii>=0; ii--)
            if(0 != check[ii])
                return false;
       
        return true;
    }

    bool isAnagram_80ms(string s, string t) {
        int ls=s.length(), lt=t.length();
       
        if(ls!=lt)
            return false;
       
        if(s==t)
            return true;

        sort(s.begin(), s.end());
        sort(t.begin(), t.end());
        return s==t;
    }

};

12 ms.