394. Decode String

Author: Tushar Borole

.idea/workspace.xml

@@ -98,6 +98,7 @@
 | 36   | [Valid Sudoku](https://leetcode.com/problems/valid-sudoku/)                                                                                 | [Itterative](valid_sudoku.js)                                                                                 | 68 ms            | 37.7 MB              | Medium     | O(1)            | O(1)             | [:link:](https://leetcode.com/problems/valid-sudoku/solution/)                 |
 | 146  | [ LRU Cache](https://leetcode.com/problems/lru-cache/)                                                                                      | [Map](lru_cache.js)                                                                                           | 216 ms           | 58.8 MB              | Medium     | O(1)            | O(1)             |                                                                                |
 | 152  | [Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)                                                         | [Dynamic Programming](max_product.js)                                                                         | 60 ms            | 35 MB                | Medium     | O(N)            | O(1)             | [:link:](https://www.youtube.com/watch?v=-rUBh45rugs)                          |
+| 394  | [Decode String](https://leetcode.com/problems/decode-string/)                                                                               | [Decode String](decode_string.js)                                                                             | 68 ms            | 33.7 MB              | Medium     |                 |                  |                                                                                |
 | 340  | [Longest Substring with At Most K Distinct Characters](https://leetcode.com/problems/longest-substring-with-at-most-k-distinct-characters/) | [Sliding Window Approach](k_distinct_characters.js)                                                           | 68 ms            | 37.1 MB              | Hard       | NlogN           |                  | [:link:](https://www.youtube.com/watch?v=MK-NZ4hN7rs&t=1936s)                  |
 | 297  | [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/)                               | [DFS Recursion](serialize_and_deserialize_binary_tree.js)                                                     | 80 ms            | 43.6 MB              | Hard       |                 |                  | [:link:](https://www.youtube.com/watch?v=suj1ro8TIVY)                          |
 

README.md

@@ -0,0 +1,51 @@
+//https://leetcode.com/problems/decode-string/
+
+/**
+ * @param {string} s
+ * @return {string}
+ */
+var decodeString = function(s) {
+  let arr = [];
+  for (let i = 0; i < s.length; i++) {
+    let isInteger = Number.isInteger(parseInt(s[i]));
+    let numberString = "";
+    while (isInteger) {
+      isInteger = Number.isInteger(parseInt(s[i + 1]));
+      numberString = numberString + s[i];
+      i++;
+      if (!isInteger) {
+        arr.push(numberString);
+      }
+    }
+    arr.push(s[i]);
+  }
+  let stack = [];
+  for (let i = 0; i < arr.length; i++) {
+    const current = arr[i];
+
+    if (current === "]") {
+      let lastElement = stack.shift();
+      let tempString = lastElement;
+      while (lastElement !== "[") {
+        lastElement = stack.shift();
+        if (lastElement !== "[") {
+          tempString = lastElement + tempString;
+        }
+      }
+      const number = stack.shift();
+      const tempOut = tempString
+        .split("")
+        .reverse()
+        .join("")
+        .repeat(number)
+        .split(""); //?
+      stack.unshift(...tempOut);
+    } else {
+      stack.unshift(current);
+    }
+  }
+
+  return stack.reverse().join("");
+};
+
+decodeString("100[abc]3[cd]ef"); //?