{ "data": { "question": { "questionId": "3561", "questionFrontendId": "3310", "boundTopicId": null, "title": "Remove Methods From Project", "titleSlug": "remove-methods-from-project", "content": "

You are maintaining a project that has n methods numbered from 0 to n - 1.

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You are given two integers n and k, and a 2D integer array invocations, where invocations[i] = [ai, bi] indicates that method ai invokes method bi.

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There is a known bug in method k. Method k, along with any method invoked by it, either directly or indirectly, are considered suspicious and we aim to remove them.

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A group of methods can only be removed if no method outside the group invokes any methods within it.

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Return an array containing all the remaining methods after removing all the suspicious methods. You may return the answer in any order. If it is not possible to remove all the suspicious methods, none should be removed.

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Example 1:

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Input: n = 4, k = 1, invocations = [[1,2],[0,1],[3,2]]

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Output: [0,1,2,3]

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Explanation:

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\"\"

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Method 2 and method 1 are suspicious, but they are directly invoked by methods 3 and 0, which are not suspicious. We return all elements without removing anything.

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Example 2:

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Input: n = 5, k = 0, invocations = [[1,2],[0,2],[0,1],[3,4]]

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Output: [3,4]

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Explanation:

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\"\"

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Methods 0, 1, and 2 are suspicious and they are not directly invoked by any other method. We can remove them.

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Example 3:

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Input: n = 3, k = 2, invocations = [[1,2],[0,1],[2,0]]

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Output: []

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Explanation:

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\"\"

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All methods are suspicious. We can remove them.

\n
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Constraints:

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Compiled with clang 17 using the latest C++ 23 standard, and libstdc++ provided by GCC 13.

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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.

\"], \"java\": [\"Java\", \"

OpenJDK 21. Using compile arguments: --enable-preview --release 21

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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.

\"], \"python\": [\"Python\", \"

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.

\"], \"c\": [\"C\", \"

Compiled with gcc 13 using the gnu11 standard.

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

\\r\\n\\r\\n

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

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For hash table operations, you may use uthash. \\\"uthash.h\\\" is included by default. Below are some examples:

\\r\\n\\r\\n

1. Adding an item to a hash.\\r\\n

\\r\\nstruct hash_entry {\\r\\n    int id;            /* we'll use this field as the key */\\r\\n    char name[10];\\r\\n    UT_hash_handle hh; /* makes this structure hashable */\\r\\n};\\r\\n\\r\\nstruct hash_entry *users = NULL;\\r\\n\\r\\nvoid add_user(struct hash_entry *s) {\\r\\n    HASH_ADD_INT(users, id, s);\\r\\n}\\r\\n
\\r\\n

\\r\\n\\r\\n

2. Looking up an item in a hash:\\r\\n

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\\r\\n

\\r\\n\\r\\n

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

\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n    HASH_DEL(users, user);  \\r\\n}\\r\\n
\\r\\n

\"], \"csharp\": [\"C#\", \"

C# 12 with .NET 8 runtime

\"], \"javascript\": [\"JavaScript\", \"

Node.js 20.10.0.

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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.

\\r\\n\\r\\n

For Priority Queue / Queue data structures, you may use 5.4.0 version of datastructures-js/priority-queue and 4.2.3 version of datastructures-js/queue and 1.0.4 version of datastructures-js/deque.

\"], \"ruby\": [\"Ruby\", \"

Ruby 3.2

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

\"], \"swift\": [\"Swift\", \"

Swift 5.10.

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You may use swift-algorithms 1.2.0 and swift-collections 1.1.0.

\"], \"golang\": [\"Go\", \"

Go 1.23

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Support https://pkg.go.dev/github.com/emirpasic/gods@v1.18.1 and https://pkg.go.dev/github.com/emirpasic/gods/v2@v2.0.0-alpha library.

\"], \"python3\": [\"Python3\", \"

Python 3.11.

\\r\\n\\r\\n

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

\\r\\n\\r\\n

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

\"], \"scala\": [\"Scala\", \"

Scala 3.3.1.

\"], \"kotlin\": [\"Kotlin\", \"

Kotlin 1.9.0.

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We are using an experimental compiler provided by JetBrains.

\"], \"rust\": [\"Rust\", \"

Rust 1.79.0. Your code will be compiled with opt-level 2.

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Supports rand v0.8 and regex\\u00a0v1 from crates.io

\"], \"php\": [\"PHP\", \"

PHP 8.2.

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With bcmath module

\"], \"typescript\": [\"Typescript\", \"

TypeScript 5.1.6, Node.js 20.10.0.

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Compile Options: --alwaysStrict --strictBindCallApply --strictFunctionTypes --target ES2022

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Your code is run with --harmony flag, enabling new ES2022 features.

\\r\\n\\r\\n

lodash.js library is included by default.

\\r\\n\\r\\n

For Priority Queue / Queue data structures, you may use 5.4.0 version of datastructures-js/priority-queue and 4.2.3 version of datastructures-js/queue and 1.0.4 version of datastructures-js/deque.

\"], \"racket\": [\"Racket\", \"

Racket CS v8.11

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Using #lang racket

\\r\\n\\r\\n

Required data/gvector data/queue data/order data/heap automatically for your convenience

\"], \"erlang\": [\"Erlang\", \"Erlang/OTP 26\"], \"elixir\": [\"Elixir\", \"Elixir 1.16 with Erlang/OTP 26\"], \"dart\": [\"Dart\", \"

Dart 3.2. You may use package collection

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Your code will be run directly without compiling

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