add : #238 Encode and Decode Strings

Author: sukyoungshin

encode-and-decode-strings/sukyoungshin.ts

@@ -0,0 +1,41 @@
+// https://neetcode.io/problems/string-encode-and-decode
+
+class Solution {
+  /**
+   * @param {string[]} strs
+   * @returns {string}
+   */
+  encode(strs) {
+    let encodedStrings: string[] = [];
+
+    for (const word of strs) {
+      const length = word.length;
+      encodedStrings.push(`${length}#${word}`);
+    }
+
+    return encodedStrings.join("");
+  }
+
+  /**
+   * @param {string} str
+   * @returns {string[]}
+   */
+  decode(str) {
+    const decodedStrings: string[] = [];
+    let position = 0;
+
+    while (position < str.length) {
+      const hashIndex = str.indexOf("#", position);
+      const length = Number(str.slice(position, hashIndex));
+
+      const start = hashIndex + 1;
+      const end = start + length;
+      const word = str.slice(start, end);
+      decodedStrings.push(word);
+
+      position = end;
+    }
+
+    return decodedStrings;
+  }
+};