Leetcode Valid-Anagram

2022-06-14 13:36

Algorithms:

#algorithm #hash_table

Data structures:

#DS #array

Difficulty:

#leetcode #coding_problem #difficulty-easy

Problem

Given two strings s and t, return true if t is an anagram of s, and false otherwise.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Follow up: What if the inputs contain Unicode characters? How would you adapt your solution to such a case?

Examples

Example 1:

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

Example 2:

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

Constraints

1 <= s.length, t.length <= 5 * 104
s and t consist of lowercase English letters.

Thoughts

The difference between this and Leetcode Ransom-Note is that ransom note checks the hash table one way, and this one is bidirectional, which means not only hash map has to be >= 0, it also has to be <= 0, which results in it can only be 0.

[!tip]- To understand that Compare this solution with Leetcode Ransom-Note#Solution to better understand what I mean.

Follow up question: Refer to this site and this answer

Solution

class Solution {
public:
  bool isAnagram(string s, string t) {
    int hashTable[26] = {};

    for (char c : s) {
      hashTable[c - 'a']++;
    }

    for (char c : t) {
      hashTable[c - 'a']--;
    }

    for (int i : hashTable) {
      if (i != 0) {
        return false;
      }
    }
    return true;
  }
};

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