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"title": "Sort Items by Groups Respecting Dependencies",
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"content": "<p>There are <code>n</code> items each belonging to zero or one of <code>m</code> groups where <code>group[i]</code> is the group that the <code>i</code>-th item belongs to and it's equal to <code>-1</code> if the <code>i</code>-th item belongs to no group. The items and the groups are zero indexed. A group can have no item belonging to it.</p>\n\n<p>Return a sorted list of the items such that:</p>\n\n<ul>\n\t<li>The items that belong to the same group are next to each other in the sorted list.</li>\n\t<li>There are some relations between these items where <code>beforeItems[i]</code> is a list containing all the items that should come before the <code>i</code>-th item in the sorted array (to the left of the <code>i</code>-th item).</li>\n</ul>\n\n<p>Return any solution if there is more than one solution and return an <strong>empty list</strong> if there is no solution.</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<p><strong><img alt=\"\" src=\"https://assets.leetcode.com/uploads/2019/09/11/1359_ex1.png\" style=\"width: 191px; height: 181px;\" /></strong></p>\n\n<pre>\n<strong>Input:</strong> n = 8, m = 2, group = [-1,-1,1,0,0,1,0,-1], beforeItems = [[],[6],[5],[6],[3,6],[],[],[]]\n<strong>Output:</strong> [6,3,4,1,5,2,0,7]\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> n = 8, m = 2, group = [-1,-1,1,0,0,1,0,-1], beforeItems = [[],[6],[5],[6],[3],[],[4],[]]\n<strong>Output:</strong> []\n<strong>Explanation:</strong> This is the same as example 1 except that 4 needs to be before 6 in the sorted list.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= m <= n <= 3 * 10<sup>4</sup></code></li>\n\t<li><code>group.length == beforeItems.length == n</code></li>\n\t<li><code>-1 <= group[i] <= m - 1</code></li>\n\t<li><code>0 <= beforeItems[i].length <= n - 1</code></li>\n\t<li><code>0 <= beforeItems[i][j] <= n - 1</code></li>\n\t<li><code>i != beforeItems[i][j]</code></li>\n\t<li><code>beforeItems[i] </code>does not contain duplicates elements.</li>\n</ul>\n",
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"code": "class Solution {\npublic:\n vector<int> sortItems(int n, int m, vector<int>& group, vector<vector<int>>& beforeItems) {\n \n }\n};",
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"code": "class Solution(object):\n def sortItems(self, n, m, group, beforeItems):\n \"\"\"\n :type n: int\n :type m: int\n :type group: List[int]\n :type beforeItems: List[List[int]]\n :rtype: List[int]\n \"\"\"\n ",
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"code": "\n\n/**\n * Note: The returned array must be malloced, assume caller calls free().\n */\nint* sortItems(int n, int m, int* group, int groupSize, int** beforeItems, int beforeItemsSize, int* beforeItemsColSize, int* returnSize){\n\n}",
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"code": "public class Solution {\n public int[] SortItems(int n, int m, int[] group, IList<IList<int>> beforeItems) {\n \n }\n}",
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"code": "/**\n * @param {number} n\n * @param {number} m\n * @param {number[]} group\n * @param {number[][]} beforeItems\n * @return {number[]}\n */\nvar sortItems = function(n, m, group, beforeItems) {\n \n};",
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"code": "# @param {Integer} n\n# @param {Integer} m\n# @param {Integer[]} group\n# @param {Integer[][]} before_items\n# @return {Integer[]}\ndef sort_items(n, m, group, before_items)\n \nend",
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"code": "class Solution {\n func sortItems(_ n: Int, _ m: Int, _ group: [Int], _ beforeItems: [[Int]]) -> [Int] {\n \n }\n}",
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"lang": "Rust",
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"code": "impl Solution {\n pub fn sort_items(n: i32, m: i32, group: Vec<i32>, before_items: Vec<Vec<i32>>) -> Vec<i32> {\n \n }\n}",
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"code": "(define/contract (sort-items n m group beforeItems)\n (-> exact-integer? exact-integer? (listof exact-integer?) (listof (listof exact-integer?)) (listof exact-integer?))\n\n )",
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"lang": "Erlang",
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"code": "-spec sort_items(N :: integer(), M :: integer(), Group :: [integer()], BeforeItems :: [[integer()]]) -> [integer()].\nsort_items(N, M, Group, BeforeItems) ->\n .",
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"code": "defmodule Solution do\n @spec sort_items(n :: integer, m :: integer, group :: [integer], before_items :: [[integer]]) :: [integer]\n def sort_items(n, m, group, before_items) do\n\n end\nend",
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"hints": [
"Think of it as a graph problem.",
"We need to find a topological order on the dependency graph.",
"Build two graphs, one for the groups and another for the items."
],
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