feat: DaleStudy#242 Valid Anagram

Author: HC-kang

valid-anagram/HC-kang.ts

@@ -0,0 +1,16 @@
+// T.C: O(n)
+// S.C: O(1)
+function isAnagram(s: string, t: string): boolean {
+  if (s.length !== t.length) return false;
+
+  const NUM_OF_ALPHA = 26;
+  const A_CODE = 'a'.charCodeAt(0);
+  const bucket = new Array(NUM_OF_ALPHA).fill(0); // S.C: O(1)
+
+  for (let i = 0; i < s.length; i++) { // T.C: O(n)
+    bucket[s.charCodeAt(i) - A_CODE]++;
+    bucket[t.charCodeAt(i) - A_CODE]--;
+  }
+
+  return bucket.every(count => count === 0);
+}