[LeetCode February Challange] Day 11 - Valid Anagram

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

Example 1:

Input: s = "anagram", t = "nagaram"
Output: true

Example 2:

Input: s = "rat", t = "car"
Output: false

Note:

You may assume the string contains only lowercase alphabets.

Follow up:

What if the inputs contain unicode characters? How would you adapt your solution to such case?

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Solution

Sorting

Time complexity : O(nlong)
Space complexity : O(1)

class Solution {
public:
    bool isAnagram(string s, string t) {
        sort(s.begin(), s.end());
        sort(t.begin(), t.end());
        return s == t;
    }
};

Hash Table

Time complexity : O(n)
Space complexity : O(1)

class Solution {
public:
    bool isAnagram(string s, string t) {
        unordered_map<char, int> m;
        for (char c: s) ++m[c];
        for (char c: t) --m[c];
        for (auto item: m) {
            if (item.second != 0)
                return false;
        }
        return true;
    }
};