首页 > 代码库 > 200. Number of Islands
200. Number of Islands
Given a 2d grid map of ‘1‘s (land) and ‘0‘s (water), count 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.
Example 1:
11110
11010
11000
00000
Answer: 1
Example 2:
11000
11000
00100
00011
Answer: 3
120/145
思路：跟word serach很像。对matrix上的每一个点进行dfs，dfs完一次就把这次搜索到的岛屿上所有点都转成0，这样下次搜索就不会搜索到重复的点。注意这种matrix搜索的base条件都是i>grid.length-1||j>grid[0].length-1||i<0||j<0。
public class Solution { public int numIslands(char[][] grid) { if(grid==null||grid.length==0) { return 0; } int count=0; for(int i=0;i<grid.length;i++) { for(int j=0;j<grid[i].length;j++) { if(grid[i][j]==‘1‘) { dfs(grid,i,j); ++count; } } } return count; } private void dfs(char[][] grid, int i, int j) { if(i>grid.length-1||j>grid[0].length-1||i<0||j<0||grid[i][j]!=‘1‘) { return; } grid[i][j]=‘0‘; dfs(grid,i-1,j); dfs(grid,i,j-1); dfs(grid,i+1,j); dfs(grid,i,j+1); } }
200. Number of Islands
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。