Valid Anagram

validAnagram.js

/**
 * @param {string} s
 * @param {string} t
 * @return {boolean}
 */
var isAnagram = function(s, t) {
    if(s.length != t.length) return false;
    
    let dict = {};
    for(let i=0; i<s.length; i++) {
        if(dict[s[i]]) dict[s[i]] += 1;
        else dict[s[i]] = 1;
    }

    for(let i=0; i<t.length; i++) {
        if(dict[t[i]] != 0) dict[t[i]] -= 1;
        if(dict[t[i]] == 0) delete dict[t[i]];
    }

    if(Object.keys(dict).length === 0) return true; 
    return false;
};


// Maintain a dictionary
// go through the first string and add all the characters in the array, if multiple occurences then increase the count
// go through the second string and reduce the count of all, if the count is 0 then remove from dictionary 
// at the end, if the dict is empty then return true, else return false

// Time: O(n)
// Space: O(n)