// Source : https://leetcode.com/problems/valid-anagram/

// Author : Hao Chen

// Date : 2015-08-16

/**********************************************************************************

*

* 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.

*

**********************************************************************************/

class Solution {

public:

//stupid way - but easy to understand - 76ms

bool isAnagram01(string s, string t) {

sort(s.begin(), s.end());

sort(t.begin(), t.end());

return s == t;

}

//using a map to count every chars in the string.

bool isAnagram02(string s, string t) {

int map[26] ={0} ; //only lowercase alphabets

//memset(map, 0, sizeof(map));

// count each char for s

for (int i=0; i<s.size(); i++) {

map[s[i]-'a']++;

}

// decrease the count for t

for (int i=0; i<t.size(); i++) {

map[t[i]-'a']--;

}

//if all alphabets is zero, then they are anagram

for (int i=0; i<sizeof(map)/sizeof(map[0]); i++) {

if (map[i]!=0) return false;

}

return true;

}

bool isAnagram(string s, string t) {

return isAnagram02(s,t); //12ms

return isAnagram01(s,t); //76ms

}

};