✨ [271] Encode and Decode Strings (Premium)

Author: enkr1

271/my_solution.js

@@ -0,0 +1,46 @@
+// 271. Encode and Decode Strings (Premium)
+
+// [“I”,“love”,“google”,“haha”,“hahaha”]
+const encode = (strList) => {
+  let positionStr = "", len = 0, str = strList.join("");
+
+  // “len,1-1,5-5,11-,..._Ilovegooglehahahahaha”
+  while (0 < strList.length) {
+    let curr = strList.shift();
+    // console.log(`curr:${curr} - ${len},${curr.length}`)
+    positionStr += `${len},${curr.length}-`;
+    len += curr.length;
+  }
+
+  return `${positionStr}_${str}`;
+}
+
+// split - pop -> string for slice(
+const decode = (str) => {
+  let splitStr = str.split("_"); // …., “Ilove…”
+  // handle edge case
+  if (2 > splitStr.length) return 404;
+
+  // “1,2-3,4-
+  let positionStr = splitStr[0], originalJoinedStr = splitStr[1];
+  positionStr = positionStr.split("-"); // [“1,2”, “3,4”]
+  positionStr.pop();
+  let decodedStrList = [];
+
+
+  while (0 < positionStr.length) {
+    let curr = positionStr.shift();
+    curr = curr.split(","); // [1, 2]
+    decodedStrList.push(originalJoinedStr.slice(parseInt(curr[0]), parseInt(curr[0]) + parseInt(curr[1])));
+  }
+
+  return decodedStrList;
+}
+
+let x = encode(["I", "love", "google", "LOL", "Lmao"]);
+console.log("x")
+console.log(x)
+
+let y = decode(x);
+console.log("y")
+console.log(y)

271/solution.js

@@ -45,6 +45,7 @@
 - [238. Product of Array Except Self](./238/)
 - [242. Valid Anagram](./242/)
 - [268. Missing Number](./268/)
+- [271. Encode and Decode Strings (Premium)](./271/)
 - [371. Sum of Two Integers](./371/)
 - [338. Counting Bits](./338/)
 - [394. Decode String](./394/)
@@ -83,5 +84,5 @@ Batch create in bash
 TODO: Add to TOC!
 -->
 ```ssh
-chapter=647 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
+chapter=271 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
 ```