{ "data": { "question": { "questionId": "1454", "questionFrontendId": "1332", "boundTopicId": null, "title": "Remove Palindromic Subsequences", "titleSlug": "remove-palindromic-subsequences", "content": "

You are given a string s consisting only of letters 'a' and 'b'. In a single step you can remove one palindromic subsequence from s.

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Return the minimum number of steps to make the given string empty.

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A string is a subsequence of a given string if it is generated by deleting some characters of a given string without changing its order. Note that a subsequence does not necessarily need to be contiguous.

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A string is called palindrome if is one that reads the same backward as well as forward.

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Example 1:

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\nInput: s = "ababa"\nOutput: 1\nExplanation: s is already a palindrome, so its entirety can be removed in a single step.\n
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Example 2:

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\nInput: s = "abb"\nOutput: 2\nExplanation: "abb" -> "bb" -> "". \nRemove palindromic subsequence "a" then "bb".\n
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Example 3:

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\nInput: s = "baabb"\nOutput: 2\nExplanation: "baabb" -> "b" -> "". \nRemove palindromic subsequence "baab" then "b".\n
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Constraints:

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Compiled with clang 11 using the latest C++ 20 standard.

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Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

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Most standard library headers are already included automatically for your convenience.

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OpenJDK 17. Java 8 features such as lambda expressions and stream API can be used.

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Most standard library headers are already included automatically for your convenience.

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Includes Pair class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.

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Python 2.7.12.

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Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

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For Map/TreeMap data structure, you may use sortedcontainers library.

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Note that Python 2.7 will not be maintained past 2020. For the latest Python, please choose Python3 instead.

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Most standard library headers are already included automatically for your convenience.

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3. Deleting an item in a hash:\\r\\n

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C# 10 with .NET 6 runtime

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Node.js 16.13.2.

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Your code is run with --harmony flag, enabling new ES6 features.

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lodash.js library is included by default.

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For Priority Queue / Queue data structures, you may use 5.3.0 version of datastructures-js/priority-queue and 4.2.1 version of datastructures-js/queue.

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Ruby 3.1

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Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms

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Go 1.21

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Python 3.10.

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PHP 8.1.

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With bcmath module

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TypeScript 5.1.6, Node.js 16.13.2.

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Run with Racket 8.3.

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