{ "data": { "question": { "questionId": "1508", "questionFrontendId": "1392", "boundTopicId": null, "title": "Longest Happy Prefix", "titleSlug": "longest-happy-prefix", "content": "

A string is called a happy prefix if is a non-empty prefix which is also a suffix (excluding itself).

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Given a string s, return the longest happy prefix of s. Return an empty string "" if no such prefix exists.

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Example 1:

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\nInput: s = "level"\nOutput: "l"\nExplanation: s contains 4 prefix excluding itself ("l", "le", "lev", "leve"), and suffix ("l", "el", "vel", "evel"). The largest prefix which is also suffix is given by "l".\n
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Example 2:

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\nInput: s = "ababab"\nOutput: "abab"\nExplanation: "abab" is the largest prefix which is also suffix. They can overlap in the original string.\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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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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Swift 5.5.2.

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Go 1.21

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Python 3.10.

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