| { |
| "id": 3308, |
| "name": "apply-operations-to-make-string-empty", |
| "difficulty": "Medium", |
| "link": "https://leetcode.com/problems/apply-operations-to-make-string-empty/", |
| "date": "2024-02-03", |
| "task_description": "You are given a string `s`. Consider performing the following operation until `s` becomes **empty**: For **every** alphabet character from `'a'` to `'z'`, remove the **first** occurrence of that character in `s` (if it exists). For example, let initially `s = \"aabcbbca\"`. We do the following operations: Remove the underlined characters `s = \"**a**a**bc**bbca\"`. The resulting string is `s = \"abbca\"`. Remove the underlined characters `s = \"**ab**b**c**a\"`. The resulting string is `s = \"ba\"`. Remove the underlined characters `s = \"**ba**\"`. The resulting string is `s = \"\"`. Return _the value of the string _`s`_ right **before** applying the **last** operation_. In the example above, answer is `\"ba\"`. **Example 1:** ``` **Input:** s = \"aabcbbca\" **Output:** \"ba\" **Explanation:** Explained in the statement. ``` **Example 2:** ``` **Input:** s = \"abcd\" **Output:** \"abcd\" **Explanation:** We do the following operation: - Remove the underlined characters s = \"**abcd**\". The resulting string is s = \"\". The string just before the last operation is \"abcd\". ``` **Constraints:** `1 <= s.length <= 5 * 105` `s` consists only of lowercase English letters.", |
| "test_case": [ |
| { |
| "label": "Example 1", |
| "input": "s = \"aabcbbca\"", |
| "output": "\"ba\" " |
| }, |
| { |
| "label": "Example 2", |
| "input": "s = \"abcd\"", |
| "output": "\"abcd\" " |
| } |
| ], |
| "constraints": [ |
| "For every alphabet character from 'a' to 'z', remove the first occurrence of that character in s (if it exists).", |
| "Remove the underlined characters s = \"aabcbbca\". The resulting string is s = \"abbca\".", |
| "Remove the underlined characters s = \"abbca\". The resulting string is s = \"ba\".", |
| "Remove the underlined characters s = \"ba\". The resulting string is s = \"\".", |
| "1 <= s.length <= 5 * 105", |
| "s consists only of lowercase English letters." |
| ], |
| "python_template": "class Solution(object):\n def lastNonEmptyString(self, s):\n \"\"\"\n :type s: str\n :rtype: str\n \"\"\"\n ", |
| "java_template": "class Solution {\n public String lastNonEmptyString(String s) {\n \n }\n}", |
| "metadata": { |
| "func_name": "lastNonEmptyString" |
| } |
| } |
