Valid Anagram #LeetCode

Question Reference:
https://leetcode.com/problems/valid-anagram/

Question Statement:

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.

Solution:


Solution 1:
Get statistics map for each string and compare these two maps.

class Solution { public: bool isAnagram(string s, string t) { std::unordered_map stats1 = getStats(s); std::unordered_map stats2 = getStats(t); if (stats1.size() != stats2.size()) { return false; } for (auto iter = stats1.begin(); iter != stats2.end(); iter++) { if (stats2.find(iter->first) == stats2.end() || stats2[iter->first] != iter->second) { return false; } } return true; } std::unordered_map getStats(string s) { std::unordered_map stats; for (char c : s) { if (stats.find(c) == stats.end()) { stats[c] = 1; } else { stats[c]++; } } return stats; } };

Solution2:
Use an array to store statistics information.

class Solution { public: bool isAnagram(string s, string t) { if (s.size() != t.size()) { return false; } vector stats(256, 0); for (char c : s) { stats[c]++; } for (char c : t) { stats[c]--; } for (int i = 0; i < 256; i++) { if (stats[i] != 0) { return false; } } return true; } };