{ "data": { "question": { "questionId": "2103", "questionFrontendId": "1992", "categoryTitle": "Algorithms", "boundTopicId": 972214, "title": "Find All Groups of Farmland", "titleSlug": "find-all-groups-of-farmland", "content": "

You are given a 0-indexed m x n binary matrix land where a 0 represents a hectare of forested land and a 1 represents a hectare of farmland.

\n\n

To keep the land organized, there are designated rectangular areas of hectares that consist entirely of farmland. These rectangular areas are called groups. No two groups are adjacent, meaning farmland in one group is not four-directionally adjacent to another farmland in a different group.

\n\n

land can be represented by a coordinate system where the top left corner of land is (0, 0) and the bottom right corner of land is (m-1, n-1). Find the coordinates of the top left and bottom right corner of each group of farmland. A group of farmland with a top left corner at (r1, c1) and a bottom right corner at (r2, c2) is represented by the 4-length array [r1, c1, r2, c2].

\n\n

Return a 2D array containing the 4-length arrays described above for each group of farmland in land. If there are no groups of farmland, return an empty array. You may return the answer in any order.

\n\n

 

\n

Example 1:

\n\"\"\n
\nInput: land = [[1,0,0],[0,1,1],[0,1,1]]\nOutput: [[0,0,0,0],[1,1,2,2]]\nExplanation:\nThe first group has a top left corner at land[0][0] and a bottom right corner at land[0][0].\nThe second group has a top left corner at land[1][1] and a bottom right corner at land[2][2].\n
\n\n

Example 2:

\n\"\"\n
\nInput: land = [[1,1],[1,1]]\nOutput: [[0,0,1,1]]\nExplanation:\nThe first group has a top left corner at land[0][0] and a bottom right corner at land[1][1].\n
\n\n

Example 3:

\n\"\"\n
\nInput: land = [[0]]\nOutput: []\nExplanation:\nThere are no groups of farmland.\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "找到所有的农场组", "translatedContent": "

给你一个下标从 0 开始，大小为 m x n 的二进制矩阵 land ，其中 0 表示一单位的森林土地，1 表示一单位的农场土地。

\n\n

为了让农场保持有序，农场土地之间以矩形的 农场组 的形式存在。每一个农场组都 仅 包含农场土地。且题目保证不会有两个农场组相邻，也就是说一个农场组中的任何一块土地都 不会 与另一个农场组的任何一块土地在四个方向上相邻。

\n\n

land 可以用坐标系统表示，其中 land 左上角坐标为 (0, 0) ，右下角坐标为 (m-1, n-1) 。请你找到所有 农场组 最左上角和最右下角的坐标。一个左上角坐标为 (r1, c1) 且右下角坐标为 (r2, c2) 的 农场组 用长度为 4 的数组 [r1, c1, r2, c2] 表示。

\n\n

请你返回一个二维数组，它包含若干个长度为 4 的子数组，每个子数组表示 land 中的一个 农场组 。如果没有任何农场组，请你返回一个空数组。可以以 任意顺序 返回所有农场组。

\n\n

示例 1：

\n\n

\"\"

\n\n
输入：land = [[1,0,0],[0,1,1],[0,1,1]]\n输出：[[0,0,0,0],[1,1,2,2]]\n解释：\n第一个农场组的左上角为 land[0][0] ，右下角为 land[0][0] 。\n第二个农场组的左上角为 land[1][1] ，右下角为 land[2][2] 。\n
\n\n

示例 2：

\n\n

\"\"

\n\n
输入：land = [[1,1],[1,1]]\n输出：[[0,0,1,1]]\n解释：\n第一个农场组左上角为 land[0][0] ，右下角为 land[1][1] 。\n
\n\n

示例 3：

\n\n

\"\"

\n\n
输入：land = [[0]]\n输出：[]\n解释：\n没有任何农场组。\n
\n\n

 

\n\n

提示：

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