{ "data": { "question": { "questionId": "200", "questionFrontendId": "200", "categoryTitle": "Algorithms", "boundTopicId": 1434, "title": "Number of Islands", "titleSlug": "number-of-islands", "content": "
Given an m x n
2D binary grid grid
which represents a map of '1'
s (land) and '0'
s (water), return the number of islands.
An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.
\n\n\n
Example 1:
\n\n\nInput: grid = [\n ["1","1","1","1","0"],\n ["1","1","0","1","0"],\n ["1","1","0","0","0"],\n ["0","0","0","0","0"]\n]\nOutput: 1\n\n\n
Example 2:
\n\n\nInput: grid = [\n ["1","1","0","0","0"],\n ["1","1","0","0","0"],\n ["0","0","1","0","0"],\n ["0","0","0","1","1"]\n]\nOutput: 3\n\n\n
\n
Constraints:
\n\nm == grid.length
n == grid[i].length
1 <= m, n <= 300
grid[i][j]
is '0'
or '1'
.给你一个由 '1'
(陆地)和 '0'
(水)组成的的二维网格,请你计算网格中岛屿的数量。
岛屿总是被水包围,并且每座岛屿只能由水平方向和/或竖直方向上相邻的陆地连接形成。
\n\n此外,你可以假设该网格的四条边均被水包围。
\n\n\n\n
示例 1:
\n\n\n输入:grid = [\n [\"1\",\"1\",\"1\",\"1\",\"0\"],\n [\"1\",\"1\",\"0\",\"1\",\"0\"],\n [\"1\",\"1\",\"0\",\"0\",\"0\"],\n [\"0\",\"0\",\"0\",\"0\",\"0\"]\n]\n输出:1\n\n\n
示例 2:
\n\n\n输入:grid = [\n [\"1\",\"1\",\"0\",\"0\",\"0\"],\n [\"1\",\"1\",\"0\",\"0\",\"0\"],\n [\"0\",\"0\",\"1\",\"0\",\"0\"],\n [\"0\",\"0\",\"0\",\"1\",\"1\"]\n]\n输出:3\n\n\n
\n\n
提示:
\n\nm == grid.length
n == grid[i].length
1 <= m, n <= 300
grid[i][j]
的值为 '0'
或 '1'
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