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            "title": "Course Schedule IV",
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            "content": "<p>There are a total of <code>numCourses</code> courses you have to take, labeled from <code>0</code> to <code>numCourses - 1</code>. You are given an array <code>prerequisites</code> where <code>prerequisites[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that you <strong>must</strong> take course <code>a<sub>i</sub></code> first if you want to take course <code>b<sub>i</sub></code>.</p>\n\n<ul>\n\t<li>For example, the pair <code>[0, 1]</code> indicates that you have to take course <code>0</code> before you can take course <code>1</code>.</li>\n</ul>\n\n<p>Prerequisites can also be <strong>indirect</strong>. If course <code>a</code> is a prerequisite of course <code>b</code>, and course <code>b</code> is a prerequisite of course <code>c</code>, then course <code>a</code> is a prerequisite of course <code>c</code>.</p>\n\n<p>You are also given an array <code>queries</code> where <code>queries[j] = [u<sub>j</sub>, v<sub>j</sub>]</code>. For the <code>j<sup>th</sup></code> query, you should answer whether course <code>u<sub>j</sub></code> is a prerequisite of course <code>v<sub>j</sub></code> or not.</p>\n\n<p>Return <i>a boolean array </i><code>answer</code><i>, where </i><code>answer[j]</code><i> is the answer to the </i><code>j<sup>th</sup></code><i> query.</i></p>\n\n<p>&nbsp;</p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2021/05/01/courses4-1-graph.jpg\" style=\"width: 222px; height: 62px;\" />\n<pre>\n<strong>Input:</strong> numCourses = 2, prerequisites = [[1,0]], queries = [[0,1],[1,0]]\n<strong>Output:</strong> [false,true]\n<strong>Explanation:</strong> The pair [1, 0] indicates that you have to take course 1 before you can take course 0.\nCourse 0 is not a prerequisite of course 1, but the opposite is true.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> numCourses = 2, prerequisites = [], queries = [[1,0],[0,1]]\n<strong>Output:</strong> [false,false]\n<strong>Explanation:</strong> There are no prerequisites, and each course is independent.\n</pre>\n\n<p><strong>Example 3:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2021/05/01/courses4-3-graph.jpg\" style=\"width: 222px; height: 222px;\" />\n<pre>\n<strong>Input:</strong> numCourses = 3, prerequisites = [[1,2],[1,0],[2,0]], queries = [[1,0],[1,2]]\n<strong>Output:</strong> [true,true]\n</pre>\n\n<p>&nbsp;</p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>2 &lt;= numCourses &lt;= 100</code></li>\n\t<li><code>0 &lt;= prerequisites.length &lt;= (numCourses * (numCourses - 1) / 2)</code></li>\n\t<li><code>prerequisites[i].length == 2</code></li>\n\t<li><code>0 &lt;= a<sub>i</sub>, b<sub>i</sub> &lt;= n - 1</code></li>\n\t<li><code>a<sub>i</sub> != b<sub>i</sub></code></li>\n\t<li>All the pairs <code>[a<sub>i</sub>, b<sub>i</sub>]</code> are <strong>unique</strong>.</li>\n\t<li>The prerequisites graph has no cycles.</li>\n\t<li><code>1 &lt;= queries.length &lt;= 10<sup>4</sup></code></li>\n\t<li><code>0 &lt;= u<sub>i</sub>, v<sub>i</sub> &lt;= n - 1</code></li>\n\t<li><code>u<sub>i</sub> != v<sub>i</sub></code></li>\n</ul>\n",
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                    "code": "class Solution {\npublic:\n    vector<bool> checkIfPrerequisite(int numCourses, vector<vector<int>>& prerequisites, vector<vector<int>>& queries) {\n        \n    }\n};",
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                    "code": "class Solution(object):\n    def checkIfPrerequisite(self, numCourses, prerequisites, queries):\n        \"\"\"\n        :type numCourses: int\n        :type prerequisites: List[List[int]]\n        :type queries: List[List[int]]\n        :rtype: List[bool]\n        \"\"\"\n        ",
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                    "code": "public class Solution {\n    public IList<bool> CheckIfPrerequisite(int numCourses, int[][] prerequisites, int[][] queries) {\n        \n    }\n}",
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                    "code": "/**\n * @param {number} numCourses\n * @param {number[][]} prerequisites\n * @param {number[][]} queries\n * @return {boolean[]}\n */\nvar checkIfPrerequisite = function(numCourses, prerequisites, queries) {\n    \n};",
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                    "code": "# @param {Integer} num_courses\n# @param {Integer[][]} prerequisites\n# @param {Integer[][]} queries\n# @return {Boolean[]}\ndef check_if_prerequisite(num_courses, prerequisites, queries)\n    \nend",
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                    "code": "func checkIfPrerequisite(numCourses int, prerequisites [][]int, queries [][]int) []bool {\n    \n}",
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                    "code": "object Solution {\n    def checkIfPrerequisite(numCourses: Int, prerequisites: Array[Array[Int]], queries: Array[Array[Int]]): List[Boolean] = {\n        \n    }\n}",
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                    "code": "class Solution {\n    fun checkIfPrerequisite(numCourses: Int, prerequisites: Array<IntArray>, queries: Array<IntArray>): List<Boolean> {\n        \n    }\n}",
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                    "lang": "Rust",
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                    "code": "impl Solution {\n    pub fn check_if_prerequisite(num_courses: i32, prerequisites: Vec<Vec<i32>>, queries: Vec<Vec<i32>>) -> Vec<bool> {\n        \n    }\n}",
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                    "code": "class Solution {\n\n    /**\n     * @param Integer $numCourses\n     * @param Integer[][] $prerequisites\n     * @param Integer[][] $queries\n     * @return Boolean[]\n     */\n    function checkIfPrerequisite($numCourses, $prerequisites, $queries) {\n        \n    }\n}",
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                    "lang": "TypeScript",
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                    "code": "function checkIfPrerequisite(numCourses: number, prerequisites: number[][], queries: number[][]): boolean[] {\n\n};",
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                    "code": "-spec check_if_prerequisite(NumCourses :: integer(), Prerequisites :: [[integer()]], Queries :: [[integer()]]) -> [boolean()].\ncheck_if_prerequisite(NumCourses, Prerequisites, Queries) ->\n  .",
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                    "code": "defmodule Solution do\n  @spec check_if_prerequisite(num_courses :: integer, prerequisites :: [[integer]], queries :: [[integer]]) :: [boolean]\n  def check_if_prerequisite(num_courses, prerequisites, queries) do\n\n  end\nend",
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                "Imagine if the courses are nodes of a graph. We need to build an array isReachable[i][j].",
                "Start a bfs from each course i and assign for each course j you visit isReachable[i][j] = True.",
                "Answer the queries from the isReachable array."
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