encode and decode strings solution

Author: hyer0705

encode-and-decode-strings/hyer0705.ts

@@ -0,0 +1,47 @@
+class Solution {
+  private DELIMITER = "*";
+
+  /**
+   * @param strs: a list of strings
+   * @returns: encodes a list of strings to a single string.
+   */
+  public encode(strs: string[]): string {
+    let encoded = "";
+
+    for (const str of strs) {
+      encoded += `${str.length}${this.DELIMITER}${str}`;
+    }
+
+    return encoded;
+  }
+
+  /**
+   * @param str: A string
+   * @returns: decodes a single string to a list of strings
+   */
+  public decode(str: string): string[] {
+    const decoded: string[] = [];
+
+    let stack: string[] = [];
+    let pointer = 0;
+
+    while (pointer < str.length) {
+      const char = str[pointer];
+
+      if (char === this.DELIMITER) {
+        let strLength: number = Number(stack.join(""));
+        stack = [];
+
+        const word = str.substring(pointer + 1, pointer + 1 + strLength);
+        pointer = pointer + 1 + strLength;
+
+        decoded.push(word);
+      } else {
+        stack.push(char);
+        pointer++;
+      }
+    }
+
+    return decoded;
+  }
+}