Add week 2 solutions: valid-anagram

Author: gitsunmin

valid-anagram/gitsunmin.ts

@@ -0,0 +1,22 @@
+/**
+ * https://leetcode.com/problems/valid-anagram/submissions
+ * time complexity : O(n)
+ * space complexity : O(n)
+ */
+function isAnagram(s: string, t: string): boolean {
+    if (s.length !== t.length) return false;
+
+    const map = {};
+
+    for (const char of s) map[char] = (map[char] ?? 0) + 1;
+
+    for (const char of t) {
+        if (map[char] !== undefined) {
+            map[char] = map[char] - 1;
+        } else return false;
+    }
+
+    for (const val of Object.values(map)) if (val !== 0) return false;
+
+    return true;
+};