feat(work): add solutions for LeetCode problems 217, 242, 189, and 49

work/Easy/Hash Table/242.valid-anagram.js

@@ -0,0 +1,55 @@
+/*
+ * 242. Valid Anagram
+ * Difficulty: Easy
+ * https://leetcode.com/problems/valid-anagram/
+ * 
+ * ──────────────────────────────────────────────────
+ * 
+ * Given two strings s and t, return true if t is an anagram of s, and
+ * false otherwise.
+ * 
+ *  
+ * 
+ * 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 * 10^4
+ * 
+ * 	• s and t consist of lowercase English letters.
+ * 
+ *  
+ * 
+ * Follow up: What if the inputs contain Unicode characters? How would
+ * you adapt your solution to such a case?
+*/
+
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+var isAnagram = function(s, t) {
+  let freq = {};
+  for (let c of s) freq[c] = (freq[c] || 0) + 1;
+  
+  for (let c of t) {
+    if(!freq[c] || freq[c] === 0){
+      return false;
+    }
+    freq[c] = freq[c] - 1;
+  }
+  return true;
+};